bluuebunny/crossref_metadata_2025 huggingface dataset:
Sodium exchange and distribution in the arterial wall
Authors: Garrahan P. , Villamil M. F. , Zadunaisky J. A.
Published: December 2017

Pieces of dog carotid artery were studied with respect to water and sodium content. Total sodium content averaged 113 ± 1.2 mm/kg fresh tissue; total water 73.6 ± 0.3% and inulin space 36.2 ± 0.5% of tissue wet wt. A total of 94.8 ± 1.3% of sodium exchanged within 6–12 min with Na22, and 97.4 ± 0.7% of the stable sodium was extracted in sodium-free solution (choline replacement). The curve of efflux of Na22 at 37 C could be decomposed into three simple exponentials with half-times of 42.5 ± 2.3 sec ( phase 1), 5.0 ± 0.3 min ( phase 2), and 71.0 ± 7.3 min ( phase 3). Exchange of sodium of phase 1 (extracellular) fitted well with a theoretical diffusion curve, showed low temperature coefficient and no potassium dependency, and was not influenced by ouabain. Exchange of sodium of phase 2 (cellular) showed high temperature coefficient and potassium dependency and was sensitive to ouabain. Calculations based on the compartmental analysis indicate a too-great intracellular sodium concentration. Binding of sodium to polyanions in the extracellular space is suggested as a possible explanation of the results.
Effect of adrenalectomy on serum and tissue amylase
Authors: Singh Ciriraj B. , Dervin Katherine E. , Gray Seymour J.
Published: December 2017

The influence of the adrenals on the maintenance and control of serum and tissue amylase was studied in rats by determining the amylase content periodically for 21 days after adrenalectomy. Liver, muscle, fat, small intestine, pancreas, and serum were investigated. Adrenalectomy markedly lowered the liver amylase throughout the 21-day period. The serum and muscle amylase fell initially and then returned to normal within 8–16 days. Pancreatic and fat amylase were not altered significantly. After an initial fall, the intestinal amylase increased to abnormally high levels, reaching a maximum at 16–21 days. Pancreatic amylase remained constant during this period and was not influenced by adrenalectomy. Surgical laparotomy alone did not alter the tissue or serum amylase significantly. It is concluded that liver amylase is partially dependent on the adrenal, and that intestinal amylase is independent of adrenal activity.
Effects of acute acid-base changes on renal hemodynamics in anesthetized dogs
Authors: Simmons Daniel H. , Olver Richard P.
Published: December 2017

Renal hemodynamics were studied in 58 experiments during acid-base disturbances in anesthetized dogs. Renal blood flow was measured with an electromagnetic flowmeter on the left renal artery. Arterial pressure was also measured and renal vascular resistance calculated. Flow and resistance were measured during respiratory acidosis and alkalosis, metabolic acidosis and alkalosis, and combined respiratory and metabolic acid-base disturbances such that arterial pH was maintained normal while pCO2 changed. pH changes were approximately 0.2 unit above and below normal and pCO2 changed to approximately double or half control. Renal vascular resistance was shown to be pCO2 dependent but not pH dependent. Doubling the control pCO2, whether pH changed or remained constant, resulted in decreased resistance (–16%) while decreasing pCO2 to approximately one-half normal resulted in increased resistance (+17%). Resistance was not influenced by the degree of renal denervation resulting from the use of the flowmeter. Changes in resistance appear likely to be related to local rather than central factors.
Effects of cerebellar lesions and stimulation on the shivering tremor
Authors: Stuart Douglas , Ott Kenneth , Eldred Earl
Published: December 2017

Shivering responses to cold have been studied in 21 cats subjected to lesions or stimulation of the cerebellum. Reluctance gauges taped to the extremity were used to sense accelerations produced by the tremor. Shivering of normal pattern was recorded within hours after total extirpation of the cerebellum and up to 4 weeks after surgery. Cats with lesions restricted to the anterior lobe also demonstrated apparently normal rhythm shivering. Comparison of regularity, amplitude, and rate of limb tremor in cats with a hemicerebellectomy, or lesions of one dentate, interpositus, or fastigial nucleus failed to reveal significant differences between the two sides of the body. Single shock or repetitive stimulation of medial cerebellar sites through indwelling electrodes primarily caused suppression of the amplitude of an ongoing tremor, but only at thresholds well above those needed to cause clonic or tonic movements of the limb. It is concluded that the presence of the cerebellum is not requisite for initiation and maintenance of shivering and that this organ has little regulatory effect on the rhythmicity of shivering.
Specific loss of the hypoglycemic control of feeding in recovered lateral rats
Authors: Epstein A. N. , Teitelbaum P.
Published: December 2017

Page 1159: A. N. Epstein and P. Teitelbaum. "Specific loss of the hypoglycemic control of feeding in recovered lateral rats." Page 1161, column 1, lines 11 and 12 should read, "The animals were not deprived of food before the tests."
Cardiac muscle mechanics in hyperosmotic solutions
Authors: Wildenthal K. , Skelton C. L. , Coleman H. N.
Published: December 2017

Page 302: K. Wildenthal, C. L. Skelton, and H. N. Coleman III. "Cardiac muscle mechanics in hyperosmotic solutions." Page 304, legend to Fig. 2, line 7 should read, "for control, and P = 0.2( e1.9l – 1)/1.9 for hyperosmolality, when calculated as the means of P and l values from individual experiments." Page 304, column 2, line 8, and Page 305, column 1, line 27, the equation should read, " P – C( eKl – 1)/ K."
Serotonin mediation of circadian periodicity of plasma 17-hydroxycorticosteroids
Authors: Krieger D. T. , Rizzo F.
Published: December 2017

Page 1703: D. T. Krieger and F. Rizzo. "Serotonin mediation of circadian periodicity of plasma 17-hydroxycorticosteroids." Page 1704, Table 1, columns 5 and 6 under the heading Significance should read, "A vs. B," "A vs. C," respectively. Page 1704, column 2, line 26 of the text should read, "In four of five instances following Monase administration." Page 1706, column 1, line 16: reference no. 7 should appear at the end of the sentence.
Mitochondrial permeability to chloride ion
Authors: Weiner MW
Published: December 2017

It is generally accepted that the inner membrane of the mitchondrion is not penetrated by chloride ion, in contrast to other biological membranes which are chloride permeable. In this report mitochondrial permeablity to chloride ion has been reevaluated by the measurement of passive swelling in isotonic chloride-containing solutions in the presence of an uncoupling agent. Under these conditions, mitochondria prepared from rat liver or beef heart show a definite uptake of wide variety of chloride salts. Mitochondrial chloride transport appears to be electrogenic, as is the transmembrane movement of the other halides. Therefore, the mitochondrial inner membrane shares with other biological membranes a definite permeability to this ubiquitous anion.
Enhancement of hypothalamic pressor responses in spontaneously hypertensive rats
Authors: Bunag RD , Eferakeya AE , Langdon DS
Published: December 2017

The cardiovascular effects of stimulating the posterior hypothalamus electrically were recorded in awake rats to permit in situ evaluation of central neural mechanisms without previous depression by anesthesia. Weak currents ineffective in normotensive or Doca-hypertensive rats elicited measurable pressor responses in spontaneously hypertensive rats, and when currents above threshold strength were used the responses were always larger in spontaneously hypertensive rats than in others. Reduction in reflex bradycardia probably contributed, at least in part, to the increased pressor responsiveness of spontaneously hypertensive rats to hypothalamic stimulation. Since pressor responses to injected norepinephrine or angiotensin were the same as or less than those in normotensive rats, it was concluded that some mechanism other than enhancement of cardiovascular reactivity is involved. Hypersensitivity of hypothalamic pressor areas was considered an attractive explanation but on the basis of the evidence available a possible hypersensitivity of other sites in the efferent neural pathway cannot be excluded.
Puromycin effect on amino acid transport: differential rates of carrier protein turnover
Authors: Phang JM , Valle DL , Fisher L , Granger A
Published: December 2017

In fetal rat calvaria, puromycin selectively inhibited the uptake of certain groups of amino acids. Puromycin treatment decreased the uptake of glycine, L-proline, and alpha-aminoisobutyric acid but was without effect on the active uptake of all other amino acids tested. In studies of alpha-aminoisobutyric acid uptake, puromycin decreased the maximal transport velocity by 70% but had no effect on the affinity of the transport system for the amino acid. With puromycin treatment, the fall-off in rates of alpha-aminoisobutyric acid uptake was first order with a half-life of 68 min. Insulin treatment increased this half-life to 118 min. These findings suggest that protein components of specific transport systems are degraded at varying rates after puromycin blockade of protein synthesis. Hormones that stimulate amino acid transport (e.g., insulin) may decrease the rate of degradation of these protein components.
Effect of hypoxia on vascular responses to the carotid baroreflex
Authors: Pelletier CL , Shepherd JT
Published: December 2017

The effect of systemic hypoxia on the vascular responses to the carotid baroreflex was studied in anesthetized, vagotomized, artificially ventilated dogs. One hindlimb, kidney, gracilis muscle, and paw were perfused at constant flow, and neurograms were obtained from renal sympathetic fibers. Bilateral carotid occlusions were performed while the animal was breathing a mixture of air and O2 (mean arterial PO2 = 106 mmHg) and again during ventilation with 10% O2 (PO2 = 40 mmHg). With occlusion, the average increase in mean aortic pressure was 36 mmHg greater during hypoxia than during normoxia and the increase in renal perfusion pressure was 87 mmHg greater; the increase in hindlimb perfusion pressure was identical in both situations. Hypoxia did not change the reflex response of the paw to carotid occlusion and increased that of the muscle vessels by only 10%; the increase in renal sympathetic activity averaged 56 plus or minus 10% more with hypoxia than with normoxia. When the carotid chemoreceptors were destroyed, the greater increase in aortic and renal pressure response to carotid occlusion during hypoxia as compared to normoxia was abolished. Thus systemic hypoxia markedly potentiates the reflex renal constriction caused by the baroreflex, and this effect is due to the carotid chemoreceptor afferent input.
Kidney function of the American eel Anguilla rostrata
Authors: Schmidt-Nielsen B , Renfro JL
Published: December 2017

Urine formation in the eel, acclimated to freshwater (FW) and seawater (SW) was studied. SW eels maintained higher plasma and urine osmotic and ionic concentrations than FW eels. Polyethylene-1,2-glycol-14C (PEG-14C) clearance was 29% greater than methoxy-inulin-3H clearance. PEG-14C clearance was considered to be the glomerular filtration rate (GFR). The GFR of SW and FW eels did not differ. Urine flow rate in SW eels was one-third of that in FW eels. The primary urinary solutes in both groups were Na and Cl. Apparently, tubular fluid secretion occurred in FW and, to a lesser degree, in SW eels. With the assumption that water reabsorption was secondary to Na reabsorption in the kidney, the clearance data were used to evaluate all possible explanations for what appeared to be fluid secretion. The data were inconsistent with the possibility that GFR had been underestimated due to glomerular sieving of PEG or active or passive reabsorption of the marker, but consistent with tubular fluid secretion. Furosemide caused diuresis in both groups of eels apparently by inhibition of Na reabsorption in the distal tubule, but it had no effect on the apparent tubular fluid secretion. Tubular ion secretion could not be conclusively implicated as a driving force for fluid secretion. However, the possibility of K, Ca, or Mg secretion in a proximal segment followed by reabsorption in a more distal part of the nephron was not ruled out.
Branchial effects of epinephrine in the seawater-adapted mullet. II. Na+ and Cl- extrusion
Authors: Pic P , Mayer-Gostan N , Maetz J
Published: December 2017

Injection of epinephrine into Mugil capito adapted to seawater is followed by a 40-60% inhibition of the Na and Cl effluxes. Simultaneously the Na influx is decreased by 30%, the overall result being a reduction of the net sodium extrusion rate by the gill. The change in Na influx is in part explained by a 75-80% decrease of the oral ingestion of seawater. This branchial adrenergic response is sensitive to alpha-blockade by phentolamine and tolazoline and insensitive to beta-blockade by propranolol. Both alpha-blockers are ineffective when injected alone. Propranolol injected alone mimics epinephrine while simultaneous injection of phentolamine blocks the response to propranolol. Rapid transfer experiments suggest that epinephrine inhibits the branchial Cl pump and its associated Na/K exchange mechanism. The leak pathway for these ions remains insensitive to epinephrine.
Pancreatic insulin release and peripheral tissue resistance in Zucker obese rats fed high- and low-carbohydrate diets
Authors: Stern JS , Johnson PR , Batchelor BR , Zucker LM , Hirsch J
Published: December 2017

An effort was made to determine to what degree the hyperinsulinemia found in the genetically obese Zucker rat is the result of the carbohydrate content of the diet. When Zucker obese rats are fed precisely the same amount of carbohydrate as lean controls and allowed to become obese by drinking vegetable oil, their pancreatic islets still release 59% more insulin than do those from lean controls. When their diet contains even more carbohydrate, fed from weaning, and they become equivalently obese, their islet insulin release is increased by an additional 46%. An obese Zucker rat fed a high-carbohydrate diet possesses muscle sensitivity to insulin and enlarged adipocytes undergoing active lipogenesis. A rat becoming equivalently obese on a high-fat diet has an absence of insulin sensitivity in muscle and diminished lipogenesis in adipocytes. Clearly, the composition of the diet plays an important role in the metabolic consequences of obesity, but neither diet nor changes in peripheral glucose metabolism can completely explain the hyperinsulinemia.
Sodium, chloride, and bicarbonate movement from plasma to cerebrospinal fluid in cats
Authors: Vogh BP , Maren TH
Published: December 2017

Rate constants have been determined for the entry of 22Na+, 36Cl minus, and H14CO3- into CSF from plasma in cats during changes in Pco2 with and without inhibition of carbonic anhydrase. The application of these rate constants to movement of unlabeled electrolytes suggests that Na+ and Cl minus enter CSF by a one-way flux into newly formed fluid, but that entering HCO3-is involved both in net accumulation in new fluid and in rapid exchange with existing HCO3-. The entering HCO3-ions are not transferred from plasma but are formed in secretory cells from dissolved CO2. The exchange component of HCO3-entry is Pco2-dependent; entry of Na+ and Cl minus is not; hence net rate of HCO3-formation estimated by difference between Na+ and Cl minus is not Pco2 dependent. The net rate of HCO3-formation lies within the availability of CO2 from blood flow to choroid plexus but is not necessarily limited to this tissue. When carbonic anhydrase is inhibited, the net rate of formation of HCO3-is close to the calculated uncatalyzed rate expected for choroid plexus. The entry of all three ions is reduced by carbonic anhydrase inhibition, but the enzyme does not seem to provide the primary signal for alteration of CSF acid-base status. Regulation of CSF pH appears to be achieved through changes in HCO3-concentration that occur subsequent to the secretion of HCO3--rich new fluid.
Tissue culture of bone marrow. V. Effect of 5Beta(H) steroids and cyclic AMP on heme synthesis
Authors: Gorshein D , Reisner EH  , gardner FH
Published: December 2017

In mice 5beta(H) steroids have been shown tostimulate heme synthesis in vivo. The current studies were undertaken to evaluate the effect of these steroids on heme synthesis by use of the "well" method of marrow culture. The 5beta(H) steroid metabolites 3alpha-hydroxy-5beta-pregnane-11, 20-dione, 3beta-hydroxy-5beta-pregnan-20-one, 3 alpha,17alpha-dihydroxy-5beta-androstan-3-one stimulated Fe uptake by human marrow explants cultured in wells. The dibutyrl analog of adenosine 3',5'-monophosphate (db cAMP) also stimulated Fe uptake. The effect of the latter compound was enhanced by theophylline. There was no additive nor synergistic effect between db cAMP and the 5beta(H) steroid metabolites. There was no inhibition of the steroid metabolite effect by either antierythropoietin serum or cyproterone. Uptake of fe was also enhanced by the cations Ca++ and Co++.
Hypothalamic cells in an area mediating ACTH release respond to right atrial stretch
Authors: Grizzle WE , Johnson RN , Schramm LP , Gann DS
Published: December 2017

The right atrium has been shown to mediate release of ACTH in response to small hemorrhage. Therefore, we sought to identify hypothalamic neurons (cat, alpha-choloralose 35-45 mg/kg) wholse firing rates were modulated by stretch of the right atrial-vena caval junction. Stretch was produced by intermittent inflation of a balloon implanted between the pericardium and the right atrium. In some cases, carotid arteries were occluded bilaterally. Previous results indicate that electrical stimulation of the medial-dorsal hypothalamus (MDH) causes prompt changes in ACTH, but stimulation in the lateral hypothalamus does not cause changes. Of 64 cells recorded in the MDH, 41 responded to atrial stretch. However, only 2 of 18 cells outside this region responded. Six cells were studied with and without carotid occlusion. Their response was dimished or absent in the absence of carotid occlusion. The results suggest that integration of afferent signals from cardiovascular receptors occurs in the MDH and that the MDH may participate in neural mediation of ACTH in response to hemodynamic changes.
Kaluresis and diuresis after administration of antidiuretic hormone to hyperkalemic dogs
Authors: Hiatt N , Miller A , Katayanagi T
Published: December 2017

Dogs infused with 2 meq KCl/kg per h exhibit electrocardiographic evidence of prelethal cardiotoxicity in about 3 h when serum potassium reaches a level between 10.2-10.5 meq/liter. During this time, their urine output of 30 ml/h is equal to the volume of KCl infused. Studies of the potassium distribution in these animals indicate that 20 percent of the infused ion is added to the extracellular fluid and red blood cell mass, 20 percent is excreted in the urine, while the remaining 60 percent is unaccounted for and presumably transferred to intracellular fluid. Dogs treated with moderately large doses of antidiuretic hormone intramuscularly before and during KCl infusion delay development of prelethal cardiotoxicity for about 5 h, with serum potassium levels comparable to those of untreated dogs. In addition, treated animals display a considerable diuresis and kaluresis with urine volumes nearly 4 times that of the volume infused. The potassium ion distribution in animals given antidiuretic hormone is much different from that of untreated dogs, with 55 percent of the infused ion found in the urine, about 15 percent in extracellular fluid and red blood cell mass, and only 30 percent presumably transferred to intracellular fluid. Transfer of potassium to intracellular fluid was calculated to be 3.1 plus or minus 0.7 meq/kg in antidiuretic-hormone-treated animals and 3.8 plus or minus 0.7 meq/kg in untreated (control) animals. Since these values are, within experimental error, quite comparable, it is possible that antidiuretic-hormone-induced kaluresis and diuresis are involved in protecting some animals from the effects of hyperkalemia by delaying the attainment of cardiotoxic blood levels.
Regulation of liver diphosphofructose phosphatase of the rat and hamster
Authors: Orengo A
Published: December 2017

The regulatory properties of D-fructose-1, 6-diphosphate 1-phosphohydrolase (FDPase, EC 3.1.3.11 ) derived from livers of the albino rat and the golden Syrian hamster have been studies. The comparative analysis of the kinetics of saturation by fructose-1, l-diphosphate (FDP) and inhibition by FDP and by the allosteric ligand adenosine 5'-monophosphate (AMP) revealed differences that may have physiological implications. The inhibition studies pointed out that liver phosphatase is under a significantly less stringent regulation in the hibernating rodent. The concentration of AMP required to produce a 50 percent inhibition was 549.5 muM at 37 degrees C, 21.4 muM at 10 degrees C, and 9.2 muM at 5 percent C for the rat; 1,122 muM at 37 degrees C, 34.3 muM at 10 degrees C, and 20.4 muM at 5 degrees C for the hamster. Urea (0.67 M) simulates the effect of low temperature, potentiating the AMP inhibition. At 5 degrees C and 4 M urea, 75 percent loss of activity was found for the rat FDPase in contrast to a 25 percent loss for the hamster. At 37 degrees C, 4 M urea had practically no effect on the FDPase of both species.
Cyclic changes in ionic composition of digesta in the equine intestinal tract
Authors: Argenzio RA , Stevens CE
Published: December 2017

Effects of diet and time after feeding on osmolality and inorganic ion content of gastrointestinal digesta were studied in 24 ponies. Animals, fed either a conventional or a low-protein, high-cellulose diet, were sacrificed 2, 4, 8, or 12 h after a meal. Animals fed the conventional diet showed cyclic variations in the ionic composition and osmolality of digesta with time after feeding. The most marked variations were seen in the contents of the stomach and small colon. However, results also indicated a cyclic appearance and disappearance of Na in large intestinal contents that correlated with net appearance and disappearance of volatile fatty acid (VFA) and H2O. Since Na and VFA were the major solutes absorbed from the cecum and colon, the ionic composition and water content of large intestinal digesta appeared largely dependent on the rate of microbial digestion. Although the large intestine of animals fed the experimental diet contained approximately twice the quanity of Na, K, Cl, VFA, and H2O, COMPENSATORY ABSORPTION BY THE MOre distal segments of colon resulted in little additional loss of these in the feces.
Melanotropic activity in extrahypophyseal regions of rodent brain: effect of age, hormones, and drugs
Authors: Rudman D , Chawla RK , Katra BS
Published: December 2017

Two or more melanotropic peptides are present in extrahypophyseal regions of mammalian brain. Previous studies showed that extrahypophyseal melanotropic activity is not influenced by hypophysectomy, adrenalectomy, or exogenous glucocorticoid. The present study investigated the possible influence of the following factors on the level of melanotropic activity in whole brain, cerebral cortex, cerebellum, midbrain, and brainstem of mouse and rat: age, sex, starvation; and of the following hormones or drugs administered by the intraperitoneal or intracerebral route: norepinephrine, dihydroxyphenylalanine, pargyline, 6-hydroxy-dopamine, alpha-methyltyrosine methyl ester, reserpine, acetylcholine, pilocarpine, atropine, serotonin, p-chlorophenylalanine, pentobarbital, pentylenetetrazol, insulin, melatonin, and cycloheximide. Only age influenced extrahypophyseal melanotropic activity. The activity per unit of tissue wet weight or of tissue protein increased in all regions progressively from birth to 1 yr of age. Extrahypophyseal melanotropic activities perunit wet weight of tissue at 50 wk averaged 4.3 times those at birth. When brain of adult rodents was fractionated by differential centrifugation, the major proportion of melanotropic activity was recovered in myelin (27-35 percent), nerve endings (20-22 percent), and mitochondria (25-30 percent). The lower activity in newborn brain resulted not onlyfrom absence of a myelin fraction, but also from lower activity at birth in nerve endings and mitochondria.
Renal glutaminases: Diamox inhibition of glutamyltransferase
Authors: Phenix P , Welbourne TC
Published: December 2017

Ammonia (NH3) production by the rat kidney was studied after an acute administration of acetazolamide (Diamox). Diamox reduced renal ammonia release (renal vein NH3 + urine NH3 - arterial NH3) 60 PERCENT IN The intact functioning kidney. Ammonia production by whole-kidney homogenates was decreased by Diamox, confirming the drug's action as inhibiting glutaminase activity. Additional studies demonstrated the inhibited glutaminase was localized in the cytoplasm; the glutaminase activity of the mitochondrial fraction was unaffected by Diamox. Isolated perfused kidneys from Diamox-treated rats confirmed that the drug reduced ammonia production by inhibiting glutamyltransferase; in addition, inhibition was shown to be of a competitive nature. We therefore conclude that cytoplasmic glutamyltransferase is the major producer of ammonia in the nonacidotic rat kidney and that it is competitively inhibited by Diamox.
Development of glomerular perfusion rate and nephron filtration rate in rats 17-60 days old
Authors: Aperia A , Herin P
Published: December 2017

The development of filtration rate and perfusion rate in superficial nephrons has been studied in 17- to 60-day-old rats with micropuncture and microsphere techniques. Recordings have also been made of total renal blood flow (RBF), cardiac output (CO), arterial blood pressure, and hematocrit. Sincle-nephron glomerular filtration rate (SNGFR) as well as glomerular perfusion rate (GPR) and RBF described a similar developmental pattern with a slower rise from 17 to 30 days of age and a faster rise thereafter. No plateau was observed. The quotient between SNGFR and GPR was constant from at least 22 days of age. Since the hematocrit was also constant after 22 days this implies a constant filtration fraction. On the basis of those findings it is suggested that GPR is the main determinator for the development of GFR. The fraction of cardiac output perfusing the kidneys increased continuously in 17- to 60-day-old rats, suggesting that the increase in RBF and GPR is due to intrarenal factors: renal vasodilatation and increase in renal vascular volume.
Localization of thirst and antidiuretic osmoreceptors by intracranial injections in rats
Authors: Peck JW , Blass EM
Published: December 2017

Eighty-six intracranial cannula placements in 51 rats were tested with unilateral, 2-mul injections of a 0.60-osmol/kg solution, sucrose dissolved in isotonic sodium chloride. To assess antidiuretic hormone (ADH) release, a water diuresis was induced and spontaneous urinations were collected and analyzed for sodium by flame photometry. On alternate test days the 0.60-osmol/kg solution was injected into sleeping rats, and latencies to drink and volume drunk were recorded. Injections at 42 placements elicited neither drinking nor adtidiuresis on two separate test days each; at 15, both antidiuresis and drinking on at least two of three tests each; at 19, drinking but not antidiuresis; at 10, antidiuresis but not drinking. Positive drinking and ADH placements were not distinctly separated. They clustered in the bed nucleus of the stria terminalis, the preoptic areas, and the anterior portions of the hypothalamus. Placements in the medial forebrain bundle and dorsal to the anterior hypothalamic area elicited thirst but not ADH release for the most part. Placements nearest the supraoptic nucleus were weak or negative for ADH release. Central nervous system osmo-receptors exist and seem not to be the neurosecretorycells. Thirst osmoreceptors and antidiuretic osmoreceptors seem to be contiguous, but distinct.
Effect of prolactin on lipoprotein lipase in crop sac and adipose tissue of pigeons
Authors: Garrison MM , Scow RO
Published: December 2017

The effect of prolactin on lipoprotein lipase activity of crop sac, omental adipose tissue, and esophagus was studied in adult female pigeons. Prolactin injected for 4 days, 1 mg/day, increased lipoprotein lipase activity from 17 to 177 U/g in crop sac and from 68 to 118 U/g in adipose tissue, but had no effect on the activity in esophagus, 4 U/g. (10 = 1 mumol of chylomicron triglyceride hydrolyzed to free fatty acid and glycerol per hour.? Prolactin increased the weight of crop sac from 1.4 to 7.2 G. The effect of prolactin on lipoprotein lipase activity and weight of crop sac occurred mostly during the 3rd and 4th days of treatment, whereas the effect on the activity of adipose tissue occurred later, during the 4th day of treatment. Crop "milk" collected from pigeons injected with 2 mg of prolactin daily for 4 days contained a small amount of lipoprotein lipase activity, 12 U/g, is smaller than 10% of that found in crop sac. The finding of markedly increased lipoprotein lipase activity in crop sac of prolactin-treated pigeons suggests that blood triglyceride may be used by crop sac for the formation of crop milk lipid.
Effect of amino acid meals on hepatic alpha-aminoisobutyrate transport and cyclic AMP
Authors: Tews JK , Colosi NW , Harper AE
Published: December 2017

Within 1.5 h after force-feeding rats one meal of enzymatic hydrolysates of casein, gelatin, lactalbumin, or yeast, alpha-aminoisobutyric acid (AIB) transport in liver slices was stimulated two- to threefold. A complete amino acid mixture also increased AIB transport. Of the 15 amino acids or derivatives tested individually, the dispensable amino acids, especially glycine and alanine, were more stimulatory than the essential amino acids; feeding a mixture of amino acids lacking glycine and alanine increased AIB uptake only slightly. The effects were significantly greater in meal-fed than in ad libitum-fed rats. Increased hepatic concentrations of cyclic AM were usually associated with the increase in AIB transport. Feeding glucose inhibited the increases in transport and cyclic AMP concentration induced by casein hydrolysate or in the stimulation of AIB transport by dietary amino acids. The increases in AIB uptake appeared unrelated to the exchange of endogenous amino acids with medium AIB.
Factors responsible for ADP-induced release reaction of human platelets
Authors: Mustard JF , Perry DW , Kinlough-Rathbone RL , Packham MA
Published: December 2017

Extensive aggregation of human platelets can be induced by ADP without secondaryaggregation or release of granule contents. This occurs with washed platelets in Tyrode solution containing 0.35% albumin, human fibrinogen, and apyrase, and in platelet-rich, heparin- or hirudin-plasma. Conditions that caused release during ADP-inducedaggregation were-citrate as the anticoagulant in platelet-rich plasma; addition of citrate (11-15 mM) to a suspension of washed platelets, or to hirudin-plasma or heparin-plasma; suspension of platelets in a medium containing magnesium but no calcium;and the presence of trace amounts of thrombin or aggregated gamma globulin in the platelet suspensions. Acetylsalicylic acid, phenylbutazone, or sulfinpyrazone inhibited secondary aggregation and release in all these circumstances. Heparin or hirudin inhibited ADP-INDUCED SECONDARY AGGREGATION AND RELEASE PROMOTED BY TRACES OF THROMBIN. Although fibrinogen is required for ADP-induced primary aggregation, it does not support secondary aggregation and release, provided that it has no clot-promoting activity. The main agent responsible for ADP-induced secondary aggregation and release in human, citrated, platelet-rich plasma appears to be sodium citrate. Suspending washed human platelets in a medium without calcium mimics the effect of citrate.
Papillary muscle dynamics: in situ function and responses of the papillary muscle
Authors: Semafuko WE , Bowie WC
Published: December 2017

Experiments were designed to 1) study in situ changes in papillary muscle length and force during the cardiac cycle, 2) investigate the relationship between papillary muscle length and maximal ventricular pressure, 3) study the effect of both positive and negative inotropic intervention on this relationship. A mercury gauge transduceror Walton-Brodie strain-gauge arch was sutured to the anterior papillary muscleand used to measure the extent of shortening or lengthening (deltaL) or force (APMF),.respectively. The anterior papillary muscle showed rapid increase of length and forcewhile contracting during isovolumic contraction and reached peak systolic length at end-isovolumic contraction or during the early injection phase. The papillary muscle was observed to shorten during the phases of ejection and isovolumic relaxation. It was concluded that changes in ventricular pressure during the cardiac cycle are associated with changes in papillary muscle length and force such that the resulting "lengthening contraction force" is appropiate for maintenance of normal atrioventricular valve function during isovolumic contraction. There was an inverse relationship between deltaL and maximal ventricular pressure such that for each increment in peak ventricular pressure there was a decrease in deltaL. The deltaL-force relationship was shifted upward and to the right by norepinephrine (NE) and isoproterenol and downward and to the left by occlusion of the posterior vena cava. Phenylephrine had little or no effect on this relationship.
Central cardiovascular dynamics of ducks
Authors: Langille BL , Jones DR
Published: December 2017

Blood pressures and flows have been recorded from the heart and arterial arches of ducks in order to present a complete picture of central hemodynamics in an avian species. An attempt has also been made to define the characteristics of the avian central circulation in terms of either "windkessel", or wave-transmission models. Mean arterial pressure (143 plus or minus 2.2 mmHg) and cardiac output (219 plus or minus 7ml/kg per min) were high compared with those of similarly sized mammals, although therewas no evidence of elevated pulmonary pressures, perhaps because of the unusual structure of the avian lung. Only 25% of the total systemic flow was distributed by the aorta, the remainder supplying the wing, flight muscles, and head via the brachiocephalic arteries. The contours of central pressure and flow waves ressembled those recorded inmammal except that significant circulation impedance modulus graphs indicated that resistance to pulsatile flow fell sharply to a minimum of 1/30th the DC value at 9-12 Hz. Flow led pressure at frequencies below 9-12Hz and pressure led flow at higherfrequencies. Impedance modulus in the pulmonary circulation fell to one-half the DC value and remained constant over a wide range of frequencies with pressure and flow being in a phase at all frequencies. Aortic pulse wave velocity varied with position inthe aorta as did the pressure pulse profile: these factors obviously limit the applicability of a windkessel model to the avian circulation.
Renal intracortical blood flow during hemorrhage: role of adrenergic mechanisms
Authors: Hardaker WT  , Graham TC , Wechsler AS
Published: December 2017

Hemorrhagic hypotensin in anesthetized dogs produced a redistribution of renal blood flow from the outer to the inner cortex. The role of adrenergic mechanisms in this redistribution was studied in anesthetized dogs using a radioactive microspheres to determine intrarenal blood flow. Neither renal denervation, nor pretreatment with reserpine altered the characteristic redistribution of renal cortical flow during hemorrhage. These observations suggest that neither intact renal nerves nor circulating catecholamines are necessary for the redistribution of renal intracortical blood flow during hemorrhagic hypotension, and the role of myogenic autoregulation is emphasized.
Oxygen-linked CO2 transport in sheep blood
Authors: Bauman R , Bauer C , Haller EA
Published: December 2017

We have analyzed oxygen-linked carbamate formation in sheep hemoglobin B by measuring a) the effect of CO2 on oxygen affinity and Bohr effect in red cell suspensions and dilute (1.3 mM Hb4) and concentrated (5 mM Hb4) hemoglobin solutions at 37 degrees C and b) CO2 binding curves of deoxygenated and oxygenated whole blood and hemoglobin solutions, respectively, at the same temperature. In the presence of CO2 both the Bohr effect and oxygen affinity were significantly lower in 1.3-mM Hb4 solutions than in either red cell suspensions or 5-mM Hb4 solutions, while in the absence of CO2 Bohr effect and oxygen affinity did not differ significantly in those preparations. Likewise, the fraction of oxygen-linked carbamate obtained from CO2 binding curves was found to be higher in 1.3-mM Hb4 (0.156 M HbCO2/M HbO2) solutions than in 5-mM Hb4 solutions (0.12 M HbCO2/M HbO2) at pH 7.2. We conclude that hemoglobin concentration affects formation of oxygen-linked carbamate. Total oxygen-linked CO2 in sheep whole blood amounted to 0.18 M CO2/M O2 of which 70% is oxygen-linked carbamate. Assuming a respiratory quotient of 0.85, the contribution of oxygen-linked CO2 to carbon dioxide exchange in sheep blood was computed to be 21%.
Rat myocardial mechanics during pressure-induced hypertrophy development and reversal
Authors: Jouannot P , Hatt PY
Published: December 2017

Moderate cardiac hypertrophy (CH) was produced in rats by abdominal aorta constriction for 5, 8, 15, 21, and 28 days. Aortic constriction release after 5, 8, and 15 days led to CH regression, which was complete within 15 days. A study of left ventricular papillary muscle mechanics during CH development demonstrated an early but transitory decrease in both maximum isometric force (Po) and maximum muscle shortening velocity (max V); in addition, the time-to-peak tension increased, and there was a decrease in isometric relaxation rate and in force-frequency relationship (negative staircase.) After CH regression, isometric relaxation and negative staircase were similar to controls, whereas the prolonged duration of contraction persisted. After release of the aortic constriction at 8 and 15 days, Po and max V were normal; however, after the earlier release (5 days), Po was higher than control, when muscle thickness was taken into consideration. These findings suggest 1) that an alteration in muscle mechanics may be related to the hypertrophy itself; 2) that anomalous excitation-contraction coupling might persist after CH regression.
Cardiac glycogen in long-evans rats: diurnal pattern and response to exercise
Authors: Segel LD , Chung A , Mason DT , Amsterdam EA
Published: December 2017

The 24-h pattern of cardiac glycogen was determined in normally active, caged male Long-Evans rats. Relatively small fluctuation was observed during a 24-h cycle with maximal difference between mean values ranging from 3.41 +/- 0.28 (dark room) to 5.15 +/- 0.19 (light room) mg glycogen/g wet wt heart, suggesting that the substantial diurnal variation of cardiac glycogen reported in Wistar rats is not a universally observed phenomenon. Cardiac glycogen during and following a single bout of moderate running was compared to a bout of strenuous running in fed male Long-Evans rats. Moderate continuous running at 20 m/min for 30 min did not decrease cardiac glycogen below the average control level (4.09 +/- 0.10 mg glycogen/g heart) but did cause a short period of supercompensation, which reached a peak of 6.27 +/- 0.19 mg/g heart at 2 h postexercise. Strenuous running in bouts at 30 m/min over a 2-h period for a distance of 1,413 m caused a significant decrease in cardiac glycogen to 2.66 +/- 0.20 mg/g heart followed by an extended period of supercompensation, which reached a peak of 9.01 +/- 1.41 mg/g heart at 4 h postexercise and remained significantly elevated during the next 13 h. Thus, the severity of exercise in normal, fed rats determines not only the extent of cardiac depletion, but also the supercompensation pattern of glycogen repletion following exercise.
Blood oxygen affinity and alveolar ventilation in relation in body weight in mammals
Authors: Lahiri S
Published: December 2017

The validity of the concept relating blood oxygen affinity and alveolar ventilation to body weight in homeothermic mammals was reexamined with blood pH used as the fixed variable. Blood Po2 at 50% saturation at pH 7.4 (P50(7.4)) and PCO2 of oxygenated blood at pH 7.4 (PCO2(7.4)) from a variety of homeothermic mammals were determined at 37 degrees C by in vitro equilibration techniques. In some species, arterial PCO2, PO2, and pH were also measured. PCO2(7.4), which was similar to arterial PCO2, showed a correlation coefficient of +0.33 with body weight over the range of 28-100,000 g and +0.90 among the species under 200 g. P50(7.4) values, which ranged from 26.0 to 38.7 mmHg for all the species, were not well correlated (r = -0.43) with body weight. For the small mammals (less than 200 g) the correlation coefficient was -0.91. In vivo P50 at the body temperature and arterial pH, although different from P50(7.4), showed a similar correlation with body weight. The lack of valid generalization suggests that body weight is only one of the composite factors that influence O2 transport systems.
Stochastic model of contractions at a point in the duodenum
Authors: Singerman RB , Macagno EO , Glover  , Christensen J
Published: December 2017

Contractions at one point in the human duodenum were studied as a time series. Manometric records were made over long time periods from the duodenum in fed human subjects. A 5-s grid was superimposed on the time axis of the records. Each 5-s interval was treated as a slow-wave cycle within which either a contraction or a no-contraction could occur. The resulting series of alternating runs of contractions and no-contractions was tested for the existence of trends. Trends were found indicating possible temporal dependence. A Markov-type model was used to try to generate data similar to the real data. Success was achieved by a model that assumed a probability of contraction dependent on the three previous slow-wave cycles. The frequency distributions obtained from the real and generated data were compared using Chi-square goodness-of-fit tests and found to be statistically similar. The correlations in time found for the contractions might be due to a time dependency in the controls for contraction over four successive slow-wave periods, 20 s in humans.
Thermoregulation in the rabbit following intracranial injection of norepinephrine
Authors: Preston E
Published: December 2017

The release of norepinephrine (NE) from nerve terminals in the anterior hypothalamic/preoptic area (AH/POA) of the rabbit may serve to raise body temperature. To further examine the putative neurotransmitter role of NE, bilateral microinjections of 5 or 10 mug NE were made into or near the AH/POA of 44 conscious rabbits exposed to an ambient temperature of 15 degrees C. Microinjections into the AH/POS did not cause fever; they either had no influence on thermoregulation or rapidly induced ear vasocilation and increased ear temperature accompanied by slight falls in rectal temperature. The latter averaged 0.32 degrees C (range: 0.16-0.45 degrees C) in 18 rabbits in which the effects were prominent. In contrast, the injection of 100 or 250 mug NE into the lateral cerebral ventricles of conscious rabbits in the 15 degrees C environment caused mean fevers of 0.62 +/- 0.0, and 1.04 +/- 0.14 degrees C (+/- SE, n equals 6), respectively, within 70 min. The febrile response to intraventricular injection of NE may be due to an action of the drug at a site other than the AH/POA. Alternatively, the response may depend critically on the particular distribution of NE that results from its diffusion from the third ventricle into the AH/POA.
Coronary vascular and myocardial responses to carotid body stimulation in the dog
Authors: Ehrhart IC , Parker PE , Weidner WJ , Dabney JM , Scott JB , Haddy FJ
Published: December 2017

Coronary vascular and myocardial responses to selective hypoxic and/or hypercapnic carotid chemoreceptor stimulation were investigated in constantly ventilated, pentobarbital or urethan-chloralose anesthetized dogs. Bilaterally isolated carotid chemoreceptors were perfused with autologous blood of varying O2 and CO2 tensions via an extracorporeal lung circuit. Systemic gas tensions were unchanged. Effects of carotid chemoreceptor stimulation on coronary vascular resistance, left ventricular dP/dt, and strain-gauge arch output were studied at natural coronary blood flow with the chest closed and during constant-flow perfusion of the left common coronary artery with the chest open. Carotid chemoreceptor stimulation slightly increased left ventricular dP/dt and slightly decreased the strain-gauge arch output, while markedly increasing systemic pressure. Coronary blood flow increased; however, coronary vascular resistance wa.as not affected. These studies show that local carotid body stimulation increases coronary blood flow but has little effect on the myocardium. The increase in coronary blood flow results mainly from an increase in systemic arterial pressure. Thus these data provide little evidence for increased sympathetic activity of the heart during local stimulation of the carotid chemoreceptors with hypoxic and hypercapnic blood.
Measurements of dog blood-brain transfer constants by ventriculocisternal perfusion
Authors: Patlak CS , Fenstermacher JD
Published: December 2017

Ventriculocisternal perfusions of mongrel dogs were performed for 1-6 h with solutions containing isotopically labeled compounds. At the conclusion of the perfusion period, serial brain samples were taken from the caudate nucleus and analyzed for radioactivity. Tissue concentration profiles were constructed from the data, and apparent tissue diffusion and capillary exchange coefficients were determined. The tissue diffusion constant of sucrose was 3 X 10(-6) cm2/s, which is approximately 45% of its free-water value. The permeability of the brain capillary complex to creatinine, sodium, and mannitol was so low that it could not be accurately measured by this technique. Capillary transfer coefficients, expressed as half-times, were determined for water, urea, and ethylene glycol; the t1/2 values were 1.5, 15, and 17 min, respectively. These numbers were converted to PS products and compared to other published values. This work suggests that the exchange of these compounds between blood and brain is partially (water) or nearly completely (urea and ethylene glycol) limited to membrane permeability.
Effects of glucagon and insulin on net hepatic metabolism of glucose precursors in sheep
Authors: Brockman RP , Bergman EN , Joo PK , Manns JG
Published: December 2017

The net hepatic metabolism of amino glycerol, lactate, and pyruvate was determined in conscious fed sheep by multiplying the venoarterial concentration differences by the hepatic blood or plasma flow. In each experiment several sets of control blood samples were taken; glucagon or insulin then was infused intraportally for 2 h during which additional samples were taken. Four types of experiments were performed: 1) glucagon infusion (150 mug/h) into normal sheep, 2) glucagon infusion (100 mug/h) into insulin-treated alloxanized sheep, 3) insulin infusion (1.17 U/h) into normal sheep, and 4) insulin plus glucose infusion (12.3 mmol/h) into normal sheep. The second group of experiments was performed to prevent reflex hyperinsulinemia, and the fourth was performed to prevent reflex hyperglucagonemia. Glucagon directly stimulated the net hepatic uptake of alanine, glycine, glutamine, arginine, asparagine, threonine, serine, and lactate. Glucagon also stimulated lipolysis in adipose tissue. Insulin, on the other hand, appeared to have a lipogenic effect on adipose tissue and to stimulate directly the uptake of valine, isoleucine, leucine, tyrosine, lysine, and alanine only at extrahepatic sites. The study showed that, in sheep, the effects of glucagon primarily are on liver, and insulin's effects primarily are on skeletal muscle and adipose tissue where it promotes protein and lipid synthesis.