bluuebunny/crossref_metadata_2025_split huggingface dataset:
Role of 5‐hydroxytryptamine in ketamine‐induced hypothermia in the rat
Authors: FAHIM I. , ISMAIL M. , OSMAN O. H. 
Published: July 2012

Summary
Intraperitoneal injection of graded doses of ketamine produced a dose‐dependent fall in body temperature of rats. Similarly, intracerebral injection of much smaller doses produced hypothermia.
Pretreatment of the rats with p‐chlorophenylalanine (PCPA) greatly attenuated the hypothermic response to ketamine whereas the intraperitoneal injection of 5‐hydroxytryptophan in PCPA‐treated rats restored the hypothermic effect of ketamine.
Depletion of the brain monoamines by reserpine completely prevented the ketamine‐induced hypothermia. Treatment with sodium diethyldithiocarbamate (DEDTC), however, did not modify the hypothermic effect of ketamine.
Pretreatment of the rats with pargyline potentiated the ketamine‐induced hypothermia.
Depletion of brain monoamines by reserpine in combination with inhibition of noradrenaline biosynthesis (DEDTC) resulted in a long lasting fall in temperature which was not modified by ketamine.
When the ambient temperature was raised from 26° C to 32° C, ketamine‐induced hypothermia was much reduced and superimposed on a hyperthermia which occurred in all animals.
It is concluded that ketamine produces hypothermia in rats possibly through the release of 5‐hydroxytryptamine in the hypothalamus and that this effect is similar in some respects to that produced by morphine in non‐tolerant rats.
The contribution of prostaglandin production to contractions of the isolated uterus of the rat
Authors: VANE J. R. , WILLIAMS K. I. 
Published: July 2012

Summary
Indomethacin and meclofenamate, both of which are potent inhibitors of prostaglandin synthetase, antagonized the contractor effects of oxytocin on the isolated uterus from the non‐pregnant rat. Contractions induced by acetylcholine or prostaglandin F2α were not antagonized.
Uteri from rats 17–22 days pregnant exhibited intermittent spontaneous contractions when used as isolated preparations. They also released prostaglandin‐like activity (mainly similar to F2α) into the bathing fluid. Both the prostaglandin release and the uterine activity were abolished by indomethacin. Activity could be restored by addition of low concentrations of prostaglandin E2 or F2α.
The release of prostaglandin F2α‐like activity by the uteri increased dramatically on the expected day of delivery (day 22).
The results add force to the hypothesis that the spontaneous activity of some isolated organs is due to an intramural prostaglandin generation, and that increased uterine prostaglandin production contributes to the expulsion of the foetus.
Effect of anti‐inflammatory drugs on the binding of calcium to cellular membranes in various human and guinea‐pig tissues
Authors: NORTHOVER B. J. 
Published: July 2012

Summary
Cellular membranes were obtained by centrifugation of homogenates of various human and guinea‐pig tissues. These membranes took up added calcium (Ca) when incubated at 25° C for 10 min in histidine buffer at pH 7·4. The uptake of Ca was increased by the presence of adenosine triphosphate (ATP).
Evidence is presented that the membrane fragments which took up Ca under these conditions were derived from the endoplasmic reticulum.
The ATP‐dependent uptake of Ca by membranes derived from guinea‐pig aortic or gastric smooth muscle or from human umbilical arterial muscle was inhibited by indomethacin in a concentration‐dependent manner.
The ATP‐dependent uptake of Ca by membranes derived from heart, brain, skeletal muscle or liver of the guinea‐pig was not inhibited by indomethacin.
Endothelial cells were obtained from the lining of the human umbilical vein. Cellular membranes were prepared from the endothelial cells by homogenization and centrifugation. The endothelial membranes took up added Ca in the presence of added ATP and this uptake was inhibited by indomethacin and also by members of a group of pharmacologically‐related drugs.
The effects of (−)‐Δ9‐tetrahydrocannabinol on reserpine‐induced hypothermia in rats
Authors: ENGLERT L. F. , HO B. T. , TAYLOR DOROTHY 
Published: July 2012

Summary
An intravenous injection into rats of 1 mg/kg (—)‐Δ9‐tetrahydrocannabinol Δ9‐THC) had no effect on rectal temperature and produced in the subcellular fractions of the brain a shift of 5‐hydroxytryptamine (5‐HT) from the particulate or ‘bound’ 5‐HT to the supernatant or ‘free’ fraction, whereas the noradrenaline (NA) decreased in both fractions.
Pretreatment of rats by an intravenous injection of 1 mg/kg Δ9‐THC three times a week for four weeks, prevented the hypothermia and the reduction in brain 5‐HT produced by an intraperitoneal injection of 15 mg/kg reserpine given 24 h after the last Δ9‐THC injection.
Pretreatment of rats by a single intravenous injection of 1 mg/kg Δ9‐THC prevented the hypothermia and reduction in brain 5‐HT produced by an intraperitoneal injection of reserpine given 1 h before. The reduction in brain NA was not prevented except at the 18 h time interval.
An injection of 1 mg/kg Δ9‐THC intravenously into rats 3 h after an intraperitoneal injection of reserpine accentuated the reserpine hypothermia as well as the reduction of 5‐HT but not of NA in the brain.
The reserpine hypothermia was not prevented by a single intravenous injection of 1 mg/kg Δ9‐THC when cinanserin, a 5‐HT inhibitor, was injected 30 min before the reserpine.
Effects of chlordane on conditioned avoidance response, brain seizure threshold and open‐field performance of prenatally‐treated mice
Authors: AL‐HACHIM G. M. , AL‐BAKER A. 
Published: July 2012

Summary
Three groups of six pregnant albino mice at the third stage of gestation were given chlordane 1 or 2·5 mg/kg body weight or olive oil 10 ml/kg. They were dosed orally for seven consecutive days.
Ten young mice, regardless of sex, were randomly selected from the progeny of each group of treated mothers and tested for conditioned avoidance response, electroshock seizure threshold, and open‐field performance.
Offspring of chlordane‐treated mice made fewer conditioned avoidance responses than the controls on each day of training.
Electroshock seizure threshold was raised.
In the open‐field test, progeny of mothers receiving the larger dose were more active than controls. A dose × days interaction indicated a complex response of the chlordane‐treated mice to experience in the open‐field.
The significance of these findings is discussed.
The effects of dipyridamole on blood flow and oxygen handling in the acutely ischaemic and normal canine myocardium
Authors: MARSHALL R. J. , PARRATT J. R. 
Published: July 2012

Summary
The effects of the intravenous administration of dipyridamole (0·25 mg/kg) were examined in a canine preparation that enabled simultaneous measurements to be made of blood flow in ischaemic and in essentially normal areas of the myocardium and also of oxygen handling (availability, consumption and extraction) in both these regions.
When administered to dogs anaesthetized with trichlorethylene 2–3 h after acute ligation of the descending branch of the left coronary artery, dipyridamole markedly increased blood flow in essentially normal regions (left circumflex flow) but failed to increase flow in the area supplied by the ligated vessel (measured by 133xenon clearance and by retrograde flow). In five of the six animals definite decreases in flow (stealing) were observed in the ischaemic region. These flow changes were related to the decreased trans‐ventricular perfusion pressure (diastolic peripheral coronary pressure minus left ventricular end‐diastolic pressure) and were accompanied by electrocardiographic evidence of increasingly severe myocardial ischaemia. The results support the suggestion that only increasing the perfusion gradient will usefully improve blood flow (and hence oxygen availability) to the acutely ischaemic myocardium.
Despite these effects on ischaemic muscle blood flow, the oxygen tension of the blood draining the infarcting muscle was markedly elevated. The conclusion is drawn that dipyridamole decreases the efficiency of the myocardial circulation by opening up vessels that do not take part in tissue exchange.
The actions of bombesin on gastric secretion of the dog and the rat
Authors: BERTACCINI G. , ERSPAMER V. , IMPICCIATORE M. 
Published: July 2012

Summary
Bombesin stimulated acid secretion from the denervated fundic pouch of the dog. Whereas the concentration of hydrochloric acid in bombesin‐produced juice was always higher than in control juice this did not occur for pepsin, the concentration of which remained below the basal values. The threshold dose of bombesin was 5–30 ng/kg by the subcutaneous route and 0·05–0·2 (μg/kg)/h by intravenous infusion. At low doses bombesin was more active than caerulein, even on a molar basis, and at high dose levels was as active as caerulein. In contrast to gastrin and caerulein, bombesin elicited a moderate secretory response also following rapid intravenous injection.
The acid secretion provoked by bombesin was almost completely inhibited by atropine and reduced by approximately 50% by hexamethonium.
Bombesin did not stimulate acid secretion in the lumen‐perfused preparation of the rat stomach when administered by subcutaneous injection (up to 10 μg/kg) or by intravenous infusion (up to 10 (μg/kg)/hour). An irregular increase in acid output was observed only following rapid intravenous injection and this was of doubtful significance.
The mechanism of the secretagogue action of bombesin on the dog stomach is discussed.
CHANGES IN MONOAMINE CONCENTRATIONS IN MOUSE BRAIN ASSOCIATED WITH ETHANOL DEPENDENCE AND WITHDRAWAL
Authors: GRIFFITHS P.J. , LITTLETON J.M. , ORTIZ A. 
Published: July 2012

Chronic administration of ethanol to mice by inhalation induced tolerance to ethanol and produced an increase in the concentration of brain monoamines.
Withdrawal of ethanol from dependent mice caused behavioural changes associated with a further transient rise in brain monoamine concentrations which then declined to control levels.
Inhibition of the withdrawal syndrome by the administration of ethanol postponed the changes in monoamines associated with withdrawal.
Administration of inhibitors of catecholamine synthesis before withdrawal of ethanol modified the withdrawal syndrome.
REVERSAL LEARNING ENHANCED BY LYSERGIC ACID DIETHYLAMIDE (LSD): CONCOMITANT RISE IN BRAIN 5‐HYDROXYTRYPTAMINE LEVELS
Authors: KING A.R. , MARTIN I.L. , MELVILLE K. ARABELLA 
Published: July 2012

Small doses of lysergic acid diethylamide (LSD) (12.5–50 μg/kg) consistently facilitated learning of a brightness discrimination reversal.
2‐Bromo‐lysergic acid diethylamide (BOL‐148), a structural analogue of LSD, with similar peripheral anti‐5‐hydroxytrypamine activity but no psychotomimetic properties, had no effect in this learning situation at a similar dose (25 μg/kg).
LSD, but not BOL‐148, caused a small but significant increase in brain 5‐hydroxytryptamine levels, but had no effect on the levels of catecholamines in the brain at 25 μg/kg.
ANTI‐INFLAMMATORY PROPERTY OF 401 (MCD‐PEPTIDE), A PEPTIDE FROM THE VENOM OF THE BEE Apis mellifera (L.)
Authors: HANSON JENNIFER M. , MORLEY J. , SORIA‐HERRERA C. 
Published: July 2012

Peptide 401, a potent mast cell degranulating factor from bee venom, substantially inhibited the oedema provoked by subplantar injection of carrageenin or intra‐articular injection of turpentine in the rat. The ED50 of 401 was c. 0.1 mg/kg. The anti‐inflammatory effect was assessed by measurement of the increased 125I‐albumin content of an injected site in comparison with an uninjected contralateral site.
Peptide 401 also suppressed the increased vascular permeability due to intradermal injection of various smooth muscle spasmogens (histamine, bradykinin, 5‐hydroxytryptamine (5‐HT), and prostaglandins).
Other comparable mast cell degranulating agents (48/80 and melittin) showed little evidence of anti‐inflammatory activity when tested at comparable dosage on turpentine arthritis and carrageenin oedema.
The anti‐inflammatory effects were not abolished by pretreatment with mepyramine and methysergide, which abolished the increased vascular permeability produced by local injection of 401.
The anti‐inflammatory action of 401 was not affected by regional denervation or pretreatment with phenoxybenzamine, and was reduced but not abolished by adrenalectomy.
Measurement of skin temperature, fractional extraction of 86Rb and blood flow in perfused mesentery gave no evidence that the anti‐inflammatory action of 401 was due to reduced tissue perfusion.
It is concluded that 401 may exert its anti‐inflammatory action directly by making the vascular endothelium anergic to phlogistic stimuli.
PHENYTOIN INHIBITION OF PARATHYROID HORMONE INDUCED BONE RESORPTION in vitro
Authors: HARRIS M. , JENKINS M.V. , WILLS M.R. 
Published: July 2012

A study is reported of the effects of phenytoin and phenobarbitone on bone calcium mobilization by parathyroid hormone in vitro.
In a therapeutic concentration (15 μg/ml), phenytoin significantly inhibited parathyroid hormone‐induced calcium release from bone.
The inhibitory effect of phenytoin on bone calcium mobilization could play a role in the maintenance of hypocalcaemia in epileptic patients on long‐term anticonvulsant drug therapy.
EFFECTS OF THE MUSCARINIC AGONIST McN‐A‐343 ON THE RELEASE BY SYMPATHETIC NERVE STIMULATION OF [3H]‐NORADRENALINE FROM RABBIT ISOLATED EAR ARTERIES AND GUINEA‐PIG ATRIA
Authors: ALLEN G.S. , RAND M.J. , STORY D.F. 
Published: July 2012

McN‐A‐343 (4‐(m‐chlorophenylcarbamoyloxy)‐2‐butynyltrimethylammonium chloride) in concentrations of 10−5 and 10−4 m inhibits the stimulation‐induced efflux of radioactivity from segments of rabbit ear artery that have previously been incubated with (–)‐[3H]‐noradrenaline, and also decreases the contractile response.
The inhibitory effects of McN‐A‐343 (10−5 m) on the efflux of radioactivity and the contractions induced by low frequencies of stimulation (2 and 5 Hz) are reversed by atropine, but atropine does not modify these effects with high frequencies of stimulation (20 and 50 Hz).
McN‐A‐343 (10−4 m) enhances the stimulation‐induced efflux of radioactivity from guinea‐pig atria that have previously been incubated with (–)‐[3H]‐noradrenaline, and prolongs the positive inotropic response. These effects are not modified by atropine.
It is concluded that McN‐A‐343 has different effects on adrenergic transmitter release in the two tissues. In the artery, it acts as an agonist on muscarinic receptors of adrenergic terminals to inhibit transmitter release at low frequencies of stimulation. In the atria it enhances transmitter efflux from the tissue, largely by inhibiting re‐uptake.
APOMORPHINE‐INDUCED AND PILOCARPINE‐INDUCED HYPOTHERMIA IN MICE: DRUG INTERACTIONS AND CHANGES IN DRUG SENSITIVITY AFTER CAUDATE NUCLEUS LESIONS
Authors: GLICK S.D. , MARSANICO R.G. 
Published: July 2012

Apomorphine and pilocarpine each produced dose‐dependent hypothermic effects in mice. However, the dose‐response curve for pilocarpine was steeper than that for apomorphine.
Bilateral lesions of the caudate nucleus produced a permanent decrease in sensitivity to apomorphine but had no effect on sensitivity to pilocarpine.
Apomorphine and pilocarpine had synergistic effects; i.e. the hypothermic effect was greater following a combination of the drugs than following either drug alone.
The effect of apomorphine was antagonized by either haloperidol or scopolamine; only scopolamine antagonized the effect of pilocarpine.
These results suggest that a mechanism involving dopaminergic neurones in the caudate nucleus has a modulatory role in temperature regulation.
TOLERANCE TO THE EFFECT OF Δ1‐TETRAHYDROCANNABINOL ON CORTICOSTERONE LEVELS IN MOUSE PLASMA PRODUCED BY REPEATED ADMINISTRATION OF CANNABIS EXTRACT OR Δ1‐TETRAHYDROCANNABINOL
Authors: PERTWEE R.G. 
Published: July 2012

Three injections of cannabis extract (500 mg/kg s.c. given over 3 or 5 days) diminished thymus gland weight but not the weights of spleen or liver in weanling female and adult male mice kept at room temperature.
Both cannabis extract (500 mg/kg s.c.) and Δ1‐tetrahydrocannabinol (Δ1‐THC; 10 and 20 mg/kg i.p.) elevated corticosterone levels in mouse plasma.
A pretreatment that consisted of three daily subcutaneous injections of 500 mg/kg of cannabis extract and that was shown to produce tolerance to the ‘cataleptic’ effect of Δ1‐THC (2 mg/kg i.v.) in mice, also produced tolerance to the effect of Δ1‐THC (10 mg/kg i.p.) on corticosterone levels in mouse plasma. However, this pretreatment did not reduce the rise in plasma corticosterone concentration produced by immobilization.
Tolerance to the effect of Δ1‐THC (10 mg/kg i.p.) on corticosterone levels in mouse plasma was also produced by the pretreatment of mice with a single injection of Δ1‐THC (10 mg/kg s.c). Three daily injections of Δ1‐THC (10 or 30 mg/kg s.c.) also produced tolerance.
In a thermoneutral environment (30–32° C) in which cannabis extract does not produce hypothermia, the drug no longer reduced thymus gland weight. However the effect of cannabis extract and of Δ1‐THC on corticosterone plasma levels was the same at room temperature as at 30–32° C. Tolerance to the latter effect of Δ1‐THC was also produced equally readily under the two conditions.
It is concluded that pretreatment with cannabis extract or Δ1‐THC can produce tolerance to the effect of Δ1‐THC on corticosterone levels in mouse plasma and does so without impairing the effect of immobilization stress on corticosterone release. In addition, both the rise in corticosterone plasma levels produced by cannabis or Δ1‐THC and the development of tolerance to this effect can still take place in the absence of hypothermia.
INVESTIGATIONS ON THE MODE OF ACTION OF ERGOTAMINE IN THE ISOLATED FEMORAL VEIN OF THE DOG
Authors: MÜLLER‐SCHWEINITZER E. , STÜRMER E. 
Published: July 2012

Experiments on spiral strips cut from the femoral vein of dogs suspended in Krebs‐Henseleit solution were carried out.
Ergotamine caused stimulation in concentrations about 350 times lower than noradrenaline (ED50 of ergotamine = 2.2 × 10−9 m; ED50 of noradrenaline = 7.6 × 10−7 M), but the maximal responses to ergotamine were only about one third those to noradrenaline.
The pA2 value of ergotamine against noradrenaline was 8.8.
The effects of ergotamine can be blocked by prior administration of phentolamine. The pA2 value for phentolamine against ergotamine was 6.8 and the pA2 value for phentolamine against noradrenaline was 7.5.
It is concluded that the stimulant action of ergotamine on smooth vascular muscle probably is mediated mainly via α‐adrenoceptors.
VOLUNTARY LITHIUM INTAKE, ‘ANTIDOTAL THIRST’ AND CONCURRENT BEHAVIOUR OF RATS
Authors: LANGHAM R.J. , SYME G.J. , SYME L.A. 
Published: July 2012

Voluntary intake of various pair combinations of fluids (100 mM, 10 mM LiCl, 10 mM NaCl, water) and body weight was measured daily in rats.
More lithium was consumed when water was available.
When offered a lithium‐sodium choice the rats did not consume significantly more saline than water on the previous trial. While saline consumption increased over the two days, lithium decreased slightly.
Following the lithium‐only trial, water and saline were provided. Marked polydipsia was observed on the first day and the rats drank more water than saline. On the second day there was a significant drop in saline intake while water consumption returned to baseline levels.
Behavioural measurements overall confirmed the depressant effect of lithium: decreased ambulation and rearing and increased time spent immobile/grooming.
These findings are discussed with reference to lithium toxicity, which may be a confounding variable in studies concerned with the effects of this salt on the behaviour of laboratory rodents. Behavioural irritability such as aggression reported in situations using long‐term lithium treatment may be reduced by provision for voluntary saline consumption.
CHOLINERGIC MECHANISMS IN CENTRAL THERMOREGULATION IN PIGEONS
Authors: CHAWLA NARESH , JOHRI M.B.L. , SAXENA P.N. , SINGHAL K.C. 
Published: July 2012

In unanaesthetized pigeons the effect on cloacal temperature was studied of acetylcholine (ACh), carbachol, atropine and (+)‐tubocurarine injected into a cannulated lateral cerebral ventricle. The experiments were carried out at an ambient temperature of 19–25°C.
ACh or carbachol injected intraventricularly produced hyperthermia, and in larger doses hyperthermia followed by hypothermia. These were central effects because they were not obtained when these drugs were injected in the same doses intravenously.
Atropine injected intraventricularly produced hypothermia which was greater and longer lasting than the hypothermia produced with the same dose of atropine injected intravenously. After the intraventricular injection of atropine the hyperthermic effects of ACh and of carbachol were abolished.
(+)‐Tubocurarine injected intraventricularly produced a long‐lasting hyperthermia in doses which had no effect on temperature when injected intravenously. After the intraventricular injection of tubocurarine the hypothermic effects of ACh and of carbachol were abolished.
It is concluded that the effects of ACh and carbachol imitate the effects of ACh released from cholinergic neurones in the central pathway involved in temperature regulation. The hypothermic effect of atropine is attributed to unmasking the activity of continuously released ACh acting on nicotinic receptors, and the hyperthermic effect of tubocurarine to unmasking the activity of continuously released ACh acting on muscarinic receptors.
EFFECT OF MORPHINE ON ADRENERGIC TRANSMISSION IN THE MOUSE VAS DEFERENS. ASSESSMENT OF AGONIST AND ANTAGONIST POTENCIES OF NARCOTIC ANALGESICS
Authors: HUGHES J. , KOSTERLITZ H.W. , LESLIE FRANCES M. 
Published: July 2012

Morphine inhibits the electrically evoked (0.1‐0.15 Hz, 1 ms) contractions of the longitudinal muscle of the mouse vas deferens but not of the rabbit, guinea‐pig, rat, cat, hamster or gerbil. This effect is stereospecific and is antagonized by naloxone or naltrexone.
Normorphine is equiactive with morphine but its effects are more rapid in onset and decline.
In the mouse vas deferens, the resting outflow of tritium‐labelled catecholamines is unaffected by morphine. The electrically evoked outflow is depressed by morphine or normorphine in a dose‐dependent manner. The ID50 for inhibition of contraction and for depression of outflow is 0.5 μM.
The relative agonist potencies of compounds without antagonist component (codeine, pethidine, morphine, normorphine, heroin, levorphanol, Ba‐20227, etorphine) show good correlation with the relative agonist potencies determined in the guinea‐pig ileum and for analgesia in man.
For compounds with dual agonist and antagonist properties, the dose‐response curves for agonist activity are shallow. When the lowest concentrations giving a depression of the contraction of the mouse vas deferens are used, a good correlation is obtained with the guinea‐pig ileum.
The relative antagonist potencies of naloxone, nalorphine, levallorphan and cyclazocine agree well with those obtained in the guinea‐pig ileum; these, in turn, correlate well with the values obtained in the morphine‐dependent monkey.
The fact that the agonist effects of drugs with dual agonist and antagonist action show little or no dependence on concentration, makes the mouse vas deferens particularly suitable for the assay of antagonist activity.
As an assay preparation, the mouse vas deferens is less robust and consistent in its responses than the guinea‐pig ileum.