bluuebunny/crossref_metadata_2025_split huggingface dataset:
PARTICIPATION OF PROSTANOIDS IN CHEMICAL ACTIVATION OF THE PERICARDIAL PRESSOR REFLEX IN DOGS
Authors: Nolan Peter N. , Luk Denise E. , Staszewska‐Woolley Janina 
Published: June 2007

SUMMARY1. Experiments were performed on anaesthetized, open‐chest dogs to determine the reflex effects on systemic blood pressure and heart rate produced by stimulation of the parietal pericardium with bradykinin, prostacyclin, prostaglandin E2 (PGE2), prostaglandin D2 (PGD2) and arachidonic acid.2. Pericardial application of bradykinin (1 μg) consistently elicited reflex increases in blood pressure and heart rate, whereas application of prostanoids or arachidonic acid in doses up to 10 μg failed to produce any cardiovascular responses.3. Indomethacin, applied either directly to the parietal pericardium (1 μg/ml) or given intravenously (5 mg/kg) caused a long lasting reduction of the reflex responses to bradykinin. The reflex effects of bradykinin could be temporarily restored by treatment of the pericardium with either prostacyclin (0.1 μg/min) or PGE2 (0.1 μg/min). PGD2 (0.1‐1 μg/min) did not influence the bradykinin induced pericardial reflex.4. Superfusion of arachidonic acid (3 μg/min) over the pericardium amplified the reflex effects of bradykinin when given before, but not when given after indomethacin treatment.5. The results indicate that locally formed prostanoids, specifically prostacyclin and PGE2, can facilitate activation of the pericardial pressor reflex by bradykinin. The findings may be relevant to the changes in cardiovascular activity occurring during pericardial inflammation.
THE EFFECT OF DOPAMINE ON TRACHEAL SMOOTH MUSCLE
Authors: Michoud M. C. , Amyot R. , St‐Jean S. , Vaillancourt R. 
Published: June 2007

SUMMARY1. Dose‐response curves to dopamine were obtained on guinea‐pig, dog and human tracheal smooth muscle.2. Dopamine produced a relaxation of the guinea‐pig tracheal chain, and this relaxation was completely blocked by propranolol. The potency of dopamine as a β‐agonist was 1/10 000 that of isoprenaline, 1/250 that of adrenaline and 1/50 that of noradrenaline.3. In human and dog tracheal smooth muscle, dopamine induced a contraction which could be entirely abolished by α‐adrenoceptor antagonists. As an α‐agonist, the potency of dopamine was 1/20 that of adrenaline and noradrenaline.4. Our data also show that a dopamine induced contraction is greatly potentiated if the smooth muscle specimen has been previously slightly contracted with histamine.5. We conclude that there are few, if any, specific dopaminergic receptors in the airways. Dopamine acts on both α‐ and β‐adrenoceptors, but in humans and dogs, its effect is predominantly on α‐adrenoceptors.
EFFECT OF SECRETAGOCUES ON PANCREATIC EXOCRINE SECRETION IN THE MONKEY AND THE DOG
Authors: Iwatsuki K. , Iijima F. , Yamagishi F. , Chiba S. 
Published: June 2007

SUMMARY1. The effects of secretin, cholecystokinin, dopamine, histamine and acetylcholine on the secretion of pancreatic juice were investigated in the monkey and the dog.2. In the resting state, bicarbonate concentration and the volume of pancreatic juice in the monkey were greater than those in the dog. However, the protein concentration of pancreatic juice in the monkey was less than that in the dog.3. Intravenous administration of secretin, cholecystokinin, histamine and acetylcholine caused a dose dependent increase in pancreatic secretion in both species. The responses in the monkey were greater than those in the dog. Dopamine caused pancreatic secretion only in the dog.4. The increase in bicarbonate concentrations of pancreatic juice induced by secretin and histamine in the monkey were greater than that in the dog. Increase in protein concentrations of the juice induced by cholecystokinin and acetylcholine in the monkey were less than that in the dog. However, pancreatic juice pH in both species was the same and was not affected by the secretagogues in the resting state or during the stimulation by secretogogues.5. From these results, it is concluded that there is a species difference in the secretory actions of the secretagogues in the monkey and the dog.
CORRELATION OF PLASMA ANGIOTENSIN II CONCENTRATION AND PLASMA RENIN ACTIVITY DURING ACUTE HYPOXIA IN DOGS
Authors: Raff Hershel , Maselli Judy , Reid Ian A. 
Published: June 2007

SUMMARY1. The effects of isocapnic hypoxia on plasma renin activity (PRA) and angiotensin II (AH) concentration were studied in anaesthetized, artificially ventilated dogs. Regression analysis of plasma All concentration vs PRA, both measured by radio‐immunoassay (RIA), was used as an index of converting enzyme activity in vivo.2. PaO2 decreased from 82 to 30 mmHg but regression analysis did not reveal any inhibition of All production within the limits of detection of this method (<20% inhibition).3. We conclude that systemic converting enzyme activity, assessed by in vivo measurement and correlation of PRA and AII, is not inhibited by severe hypoxia.
COMPARISON OF THE AFFINITY OF SECOVERINE FOR SOME MUSCARINIC RECEPTORS
Authors: Choo L. K. , Mitchelson F. 
Published: June 2007

SUMMARY1. The selective muscarinic receptor antagonist secoverine was found to have a similar affinity for muscarinic receptors in the guinea‐pig left atrium and ileal longitudinal muscle as well as in the rat urinary bladder and ileum.
NALOXONE DOES NOT REVERSE ETHANOL ANALGESIA IN MAN
Authors: Saddler J. M. , James M. F. M. , Harington A. P. 
Published: June 2007

SUMMARY1. The effects of intravenously administered ethanol and morphine on pain threshold, reaction time, motor skills and short‐term memory were investigated, and the ability of naloxone to reverse any changes was studied.2. Morphine (loading dose 0.2 mg/kg with an infusion of 0.004 mg/kg per min) and ethanol (loading dose 0.75 ml/kg with an infusion of 0.0025 ml/kg per min) produced a similar increase in pain threshold of 6.3 (s.e.m. = 1.5, n= 8) pain units and 7.7 (s.e.m. = 1.9, n= 8) pain units, respectively. Naloxone 0.015 mg/kg produced a significant reduction in pain threshold in the morphine group, but not in the ethanol group, and there was a significant difference between the groups following naloxone (P<0.05, t‐test, 7 d.f.).3. Ethanol produced a significantly greater deterioration in motor skills than did morphine (P<0.05, t‐test, 7 d.f.) and performance in both groups was improved following naloxone (P<0.05, t‐test, 7 d.f.).4. There was no significant change in the other modalities studied.5. It is concluded that the reversal of ethanol effects by naloxone is probably due to a non‐specific analeptic action rather than blockade of opioid receptors.
NALOXONE BLOCKS THE CARDIAC EFFECTS OF MYOCARDIAL ISCHAEMIA AND REPERFUSION IN THE RAT ISOLATED HEART
Authors: Zhan Z. Y. , Lee A. Y. S. , Wong T. M. 
Published: June 2007

SUMMARY1. The effects of naloxone on contractility and cardiac rhythm were studied in the rat isolated perfused heart during myocardial ischaemia and reperfusion.2. Pretreatment of the rat isolated perfused heart with naloxone abolished the reduction in left ventricular pressures and attenuated greatly the arrhythmias due to myocardial ischaemia and reperfusion.3. Administration of naloxone into the fibrillating rat isolated heart induced by myocardial ischaemia and reperfusion also attenuated the arrhythmias in a dose‐dependent manner.4. The results indicate a possible involvement of the endogenous opioid peptides in the cardiac effects due to myocardial ischaemia and reperfusion. The anti‐arrhythmic effect of naloxone has great clinical implications.
CARDIAC ANTIARRHYTHMIC EVALUATION OF NALOXONE WITH OR WITHOUT PROPRANOLOL USING A MODIFIED CHLOROFORM‐HYPOXIA SCREENING TEST IN THE RAT
Authors: Wong T. M. , Lee A. Y. S. 
Published: June 2007

SUMMARY1. The effects of naloxone and propranolol on cardiac arrhythmias and durations from respiratory arrest to ventricular asystole and cardiac standstill were studied in unanaesthetized young rats induced to suffer respiratory arrest and exhibit ventricular fibrillation (VF) by a modified chloroform hypoxia technique.2. Both naloxone and propranolol reduced the incidence of VF dose dependently, indicating that they have antiarrhythmic effects. Addition of naloxone to propranolol shifted the dose‐response curve of propranolol to the left significantly, indicating an additive effect of the two drugs in their antiarrhythmic activity.3. Both naloxone and propranolol prolonged the duration from respiratory arrest to ventricular asystole. However, joint administration of both did not further prolong this duration indicating an absence of additive effects.4. Naloxone prolonged the duration from respiratory arrest to cardiac standstill, indicating that naloxone prolonged the survival time. In contrast, propranolol did not produce the same effect.5. That naloxone both produced antiarrhythmic effect and prolonged the survival time whereas propranolol only corrected cardiac arrhythmias suggests that the antiarrhythmic effect of naloxone may not result in prolongation of survival time and that different mechanisms may be involved in the antiarrhythmic effect.
PLASMA NORADRENALINE AND ITS RELATIONSHIP TO PLASMA OESTRADIOL IN NORMAL WOMEN DURING THE MENSTRUAL CYCLE
Authors: Davidson Lisa , Rouse Ian L. , Vandongen Robert , Beilin Lawrence J. 
Published: June 2007

SUMMARY1. In order to investigate a possible relationship beween sympatho‐adrenal neuronal activity and the endocrine changes during the menstrual cycle, free and sulphate‐conjugated plasma catecholamines and oestradiol were measured under carefully controlled conditions in 26 normal menstruating women.2. Plasma oestradiol levels were generally higher during the luteal compared with the follicular phase which corresponded to the self‐reported day of the cycle.3. Free plasma noradrenaline concentration was higher during the luteal phase (P= 0.02) and was positively correlated with plasma oestradiol concentration (r= 0.40, P= 0.023). These relationships were not present for plasma adrenaline.4. It is conceivable that the higher luteal phase noradrenaline is causally related to the higher oestradiol levels, leading to incomplete inactivation by reducing tissue uptake or competitive inhibition of catechol‐O‐methyl transferase.5. As sulphated noradrenaline was not significantly different between the follicular and luteal phases, competitive inhibition of phenolsulphotransferase by oestradiol was considered unlikely.
FURTHER INVESTIGATIONS ON THE α1‐ADRENOCEPTOR BLOCKING PROPERTIES OF AR‐C 239 IN RATS
Authors: Huchet Anne‐Marie , Andréjak Michel , Lucet Bernadette , Gautret Bruno , Doursout Marie‐Françoise , Ostermann† Gérard , Schmitt Henri 
Published: June 2007

SUMMARY1. AR‐C 239, a new α‐adrenoceptor blocking drug, appears to act selectively on α1 sites in rats. At peripheral sites, this drug did not change the tachycardia induced by spinal sympathetic outflow stimulation in pithed rats, and did not antagonize the inhibitory effects of clonidine on this preparation. In addition, AR‐C 239 showed predominant α1‐adrenoceptor blocking properties in the bisected rat vas deferens preparation. AR‐C 239 did not prevent or reverse the centrally mediated hypotensive and bradycardic actions induced by clonidine, in intact animals.2. In conclusion, AR‐C 239 seems to be a very useful tool for the characterization of peripheral and central α1‐adrenoceptors, in this animal species.
THE ANTICHOLINESTERASE ACTIVITY OF MEFLOQUINE
Authors: Lim L. Y. , Go M. L. 
Published: June 2007

SUMMARY1. The characteristics of the inhibition of electric eel acetylcholinesterase (AChE) and horse serum butyrylcholinesterase (BChE) by the antimalarial agents mefloquine, chloroquine, amodiaquine and amopyroquine were determined.2. The antimalarials were found to be non‐competitive inhibitors of both AChE and BChE. In both enzyme systems, inhibitory potencies were in the order amodiaquine > amopyroquine > chloroquine > mefloquine.3. The low inhibitory potency of mefloquine may account in part for the appearance of gastrointestinal and central nervous system disturbances only at high doses of the drug.
THE EFFECT OF AGING ON α‐ADRENOCEPTORS AND THEIR RESPONSES IN RABBITS
Authors: Hamilton C. A. , Dalrymple H. W. , Jones C. R. , Reid J. L. 
Published: June 2007

SUMMARY1. The effects of age on α‐adrenoceptor responses, sensitivity and number were studied in rabbits aged from 1 to 36 months.2. Three types of investigation were carried out: conscious animal studies, isolated tissue studies and radioligand binding studies.3. Specific [3H]‐prazosin binding decreased with age in both spleen and heart suggesting that the number of α1‐receptors declined at least in the tissues studied. The specific binding of [3H]‐clonidine to spleen membranes and [3H]‐yohimbine to platelets was not affected by age.4. In vitro responsiveness to α‐adrenoceptor agonists decreased with age in abdominal aorta and renal artery, while the affinity of adrenoceptors for prazosin (pA2) was not altered. The decrease may be non‐specific as responses to potassium were also altered. No change in α2‐adrenoceptor mediated platelet aggregation was observed.5. No change in pressor or depressor responses to full adrenoceptor agonists or to antagonists was observed in vivo. However, responses to clonidine, which is a partial agonist at α1‐adrenoceptors, were decreased.6. While aging influenced α‐adrenoceptor subtypes differently, there was no direct relation between functional changes and number of receptors.
EFFECTS OF D‐PENICILLAMINE ON COLLAGEN BIOSYNTHESIS BY FIBROBLAST CELL CULTURES
Authors: Chamson Annette , Frey Jacques 
Published: June 2007

SUMMARY1. The effects of d‐penicillamine on collagen and total protein synthesis by fibroblast cell cultures were studied.2. High concentration of d‐penicillamine (10 mmol/1) produced a toxic effect consisting of inhibition of growth and a non‐specific increase in protein synthesis.3. A low concentration of d‐penicillamine (100 μmol/1) decreased the biosynthesis of both type I and type III collagens.
DIGITALIS RECEPTORS AND DIGOXIN SENSITIVITY IN RENAL FAILURE
Authors: Malini Pier Luigi , Strocchi Enrico , Feliciangeli Giorgio , Buscaroli Andrea , Bonomini Vittorio , Ambrosioni Ettore 
Published: June 2007

SUMMARY1. The number and the in vitro and in vivo affinity of digitalis receptors for digoxin were measured in patients with normal renal function and in uraemics.2. In uraemic patients the number of receptors was decreased. Although their in vitro affinity for digoxin was unchanged the in vivo affinity was decreased, probably due to hyperkalaemia.3. These findings provide a possible pharmacodynamic explanation for decreased activity of cardiac glycosides in chronic renal failure.
CARDIOVASCULAR EFFECTS OF BROVINCAMINE AND POSSIBLE MECHANISMS INVOLVED
Authors: Kushiku K. , Katsuragi T. , Mori R. , Morishita H. , Furukawa T. 
Published: June 2007

SUMMARY1. Cardiovascular effects of brovincamine (BV) and possible modes of action were studied in dogs, rabbits and guinea‐pigs.2. In pentobarbitone‐anaesthetized dogs, intravenous administration of BV (1.6–12.8 mg/kg) induced a dose‐dependent decrease of blood pressure and heart rate, a slight and transient stimulation of respiration, and a prolongation of the R‐R interval in ECG without changes of wave pattern.3. In the isolated atria of guinea‐pigs, BV showed no effect at 10−7 and 10−6 g/ml, but dose‐dependently inhibited both myocardial contractile force and heart rate at the higher concentrations of 10−5 and 10−4 g/ml.4. In pentobarbitone‐anaesthetized dogs, BV (0.1–1.6 mg/kg) administered to the vertebral or carotid artery dose‐dependently increased the blood flow in the respective artery.5. Intravenous administration of BV (0.8–12.8 mg/kg) also exhibited a dose‐dependent increase of the vertebral and carotid blood flow, but the increase was a little reduced at the higher dose of 12.8 mg/kg, probably resulting from marked hypotension and negative chronotropism. Intravenous administration of BV at 6.4 mg/kg induced a marked increase of the coronary flow, a slight increase of the renal flow and a slight decrease of the femoral flow.6. 11–Bromovincaminic acid (BVA, 0.1, 0.2 mg/kg), a major metabolite of BV, given intravenously or to the internal carotid artery, did not exert actions on the blood pressure, heart rate and carotid blood flow, implying that it is an inactive metabolite.7. In rabbit pulmonary arterial strips, BV showed no influence on effects of noradrenaline and adenosine but inhibited KC1‐induced contracture. This inhibitory effect of BV, but not papaverine, was antagonized by an increase of external Ca2+ concentration.8. In conclusion, BV rather selectively increases the cranial and coronary blood flow. The vasodilative effects of BV seem to involve an inhibition of depolarization dependent Ca2+ slow channel. A major metabolite of BV, BVA, is inactive.
KETANSERIN DOES NOT PREVENT ACTH‐INDUCED HYPERTENSION IN SHEEP
Authors: Nelson Mark A. , Coghlan John P. , Denton Derek A. , Whitworth Judith A. , Scoggins Bruce A. 
Published: June 2007

SUMMARY1. The role of serotonin (5HT) in the pathogenesis of ACTH‐induced hypertension in sheep has been examined.2. The pressor responses to injections of 5HT (0.1–30 μg/kg) were similar in normotensive and hypertensive sheep.3. Prior treatment with the 5HT2 receptor antagonist ketanserin had no effect on the development of hypertension produced by ACTH administration.
LACK OF EFFECT OF CHLORAMPHENICOL ON MONOAMINE, DIAMINE AND PLASMA AMINE OXIDASE ACTIVITIES
Authors: Ali B. H. 
Published: June 2007

SUMMARY1. Chloramphenicol treatment in rabbits (60 mg/kg i.m. for 5 days) did not affect significantly (P > 0.1) the activities of monoamine oxidase (MAO) or diamine oxidase (DAO) in liver, heart or brain.2. Plasma amine oxidase (PAO) was not significantly inhibited (P>0.1) in goats treated with chloramphenicol (60 mg/kg i.m. for 5 days).3. Chloramphenicol (2×10−3 mol/l) preincubated with rabbit hepatic MAO had no significant effect (P>0.1) on the enzyme activity.
IMPORTANCE OF ENDOGENOUS VASOPRESSIN IN THE HYPERTENSIVE AND BRADYCARDIC RESPONSE TO CENTRAL α1‐ADRENERGIC STIMULATION
Authors: Hiwatari Masao , Johnston Colin I. 
Published: June 2007

SUMMARY1. To determine the interaction between α1‐adrenergic and vasopressinergic mechanisms in the central regulation of cardiovascular functions, the effects of intracerebroventricular (i.c.v.) administration of the α1‐agonists, methoxamine and phenylephrine, were examined in conscious Long‐Evans (LE) rats and Brattleboro rats with hereditary hypothalamic diabetes insipidus (DI).2. In LE rats, i.c.v. methoxamine and phenylephrine (3–30 μg/kg) increased blood pressure and decreased heart rate in a dose‐related manner, while they had no detectable cardiovascular effects in DI rats.3. Neither i.c.v. (0.5 ng/kg per min, 1 h) nor intravenous (i.v., 2 ng/kg per min, 2 h) infusion of vasopressin (AVP) restored the cardiovascular response to i.c.v. phenylephrine in DI rats.4. In LE rats, however, i.v. pretreatment with the specific antagonist to the pressor effect of AVP, d(CH2)5Tyr(Me)AVP (10 μg/kg), attenuated the hypertensive and bradycardic effects of i.c.v. phenylephrine, while i.c.v. pretreatment with AVP antagonist (300 ng/kg) did not alter the cardiovascular response to i.c.v. α1‐agonist.5. The cardiovascular response to i.c.v. phenylephrine was blocked by i.c.v. pretreatment with the α1‐antagonist, prazosin (2 μg/kg).6. Intracerebroventricular phenylephrine increased plasma AVP levels 14‐fold without affecting plasma angiotensin II levels.7. The present study clearly demonstrated that endogenous AVP plays a significant role in the cardiovascular response to i.c.v. α1‐agonist.
POTENTIATION OF ACTH HYPERTENSION IN MAN WITH SALT LOADING
Authors: Whitworth Judith A. , Saines Dianne , Scoggins Bruce A. 
Published: June 2007

SUMMARY1. ACTH 1 mg/day for 5 days raises systolic blood pressure (SBP) in normotensive and hypertensive subjects on a fixed electrolyte intake of 100 mmol/day sodium (Na) and potassium (K) (Whitworth et al. 1983).2. The present study examined the effect of Na intake in the high normal range on the haemodynamic and metabolic responses to ACTH.3. ACTH administration on a 200–300 mmol Na intake increased SBP by 35 mmHg (s.e.m. = 11, n= 5) compared with the 22 mmHg (s.e.m. = 4, n= 12) rise seen on a 100 mmol Na intake in our previous study.4. These studies suggest that the effects of adrenocortical steroids on blood pressure in man may be magnified by increasing dietary Na intake.
A RANDOMIZED CONTROLLED TRIAL OF THE EFFECT OF ALCOHOL CONSUMPTION ON BLOOD PRESSURE
Authors: Puddey I. B. , Beilin L. J. , Vandongen R. , Rouse I. L. 
Published: June 2007

SUMMARY1. Forty‐six healthy normotensive male drinkers participated in a randomized, controlled, crossover trial to study the effects of varying alcohol intake on blood pressure.2. Alcohol consumption (calculated from weekly diaries) was reduced from 336.3 (s.e.m. = 20.2) to 64.5 (s.e.m. = 5.6) ml ethanol/week by drinking low alcohol content beer alone.3. Systolic blood pressure fell significantly during reduction of alcohol intake and rose again when normal drinking habits were resumed, the mean difference during the last 2 weeks of normal or low alcohol intake being 3.8 mmHg.4. This effect of alcohol on blood pressure was independent of a small but significant decrease in weight following reduction of alcohol intake.5. The change in blood pressure correlated with change in alcohol consumption (r= 0.53, P<0.001) with a 1 mmHg fall predicted for each 100 ml of reduction in ethanol intake/week.6. We conclude that regular moderate alcohol consumption has a direct (but reversible) pressor effect in normotensive men.
A RANDOMIZED CONTROLLED TRIAL OF WEIGHT REDUCTION AND METOPROLOL IN THE TREATMENT OF HYPERTENSION IN YOUNG OVERWEIGHT PATIENTS
Authors: MacMahon S. W. , Macdonald G. J. , Bernstein L. , Andrews G. , Blacket R. B. 
Published: June 2007

SUMMARY1. The effects of weight reduction and metoprolol (100 mg, b.d.) in the treatment of hypertension (diastolic blood pressure 90–109 mmHg) in 56 young, overweight patients were investigated in a randomized placebo controlled trial. After a 4‐week baseline, subjects were followed up for 21 weeks.2. In the weight reduction group, the fall in systolic and diastolic blood pressure (13/10 mmHg), associated with a mean group weight loss of 7.4 kg, was greater (P<0.001) than that in the placebo group (7/3 mmHg); the fall in diastolic pressure but not systolic pressure was also greater than that in the metoprolol group (10/6 mmHg). At the end of follow‐up, 50% of the weight reduction group, 39% of the metoprolol group and 17% of the placebo group had a diastolic blood pressure of less than 90 mmHg.3. In the weight reduction group there was a fall in total cholesterol and the ratio of total to HDL‐cholesterol (P<0.001); in the metoprolol group there was a fall in HDL‐cholesterol and an increase in the ratio of total to HDL‐cholesterol (P<0.001).4. It was concluded that a vegetarian diet may have an adjunctive role in control of mild hypertension, but that in view of likely problems with acceptability those dietary components responsible for the blood pressure differences need to be identified.
INCREASED PLASMA NORADRENALINE DURING LOW DOSE ADRENALINE INFUSION IN RESTING MAN AND DURING SYMPATHETIC STIMULATION
Authors: Musgrave I. F. , Bachmann A. W. , Jackson R. V. , Gordon R. D. 
Published: June 2007

SUMMARY1. Both resting and stimulated (straight‐leg raising and head‐up tilt) levels of arterial and venous plasma noradrenaline were significantly higher during low‐dose adrenaline infusion in five mild hypertensive and four normotensive patients with one adrenal.2. Repeat adrenaline infusions in the five hypertensive patients while measuring noradrenaline clearance (3H‐noradrenaline constant infusion) achieved similar levels of plasma adrenaline, and similar increases in plasma noradrenaline, within five min of achieving target infusion rate. Increased plasma noradrenaline was not explained by reduced clearance.3. These results are consistent with the hypothesis that physiological concentrations of adrenaline are capable of facilitating noradrenaline release in man.