. The effect of clonidine hydrochloride has been studied in unanaesthetized albino rats, cats, dogs, guineapigs, pigeons and albino rabbits. A lateral ventricle was chronically cannulated for making intraventricular injections. Clonidine provoked a fall in body temperature by its central action. The rabbit was the least sensitive. It is suggested that the hypothermic effect is mediated through activation of central (-adrenoceptors and it exhibits, like noradrenaline, species dependence and is blocked by phenoxybenzamine in the rat and the cat. Behavioural manifestations of sympathetic stimulation, emesis, chewing, sedation etc. also accompany intraventricular injections of clonidine. The effect of noradrenaline in the rabbit is an excitatory one, that is, a rise in body temperature. Clonidine, which is believed to mimic the depressant effects of central ( -adrenoceptor activation, does not produce this effect of noradrenaline in the rabbit.

. A toxic principle (FT) isolated from Sphaeroides oblongus, a poisonous fish, showed dose-dependent (25-800 'g/kg) decreasein cardiac rate and blood pressure accompanied by respiratory depression including transient apnoeic phases in urethane-anaesthetized cat preparations. A peripheral mechanism of action comprising blockade of sympathetic (vasomotor) axonal conductiion, a transient myocardial depression and partial direct musculotropic effect is suggested to be responsible for the bradycardia, hypotension and respiratory depression.

. The present study was planned to evaluate the mechanism of acute and chronic stress ulceration on pylorus ligated rats and to correlate the aggressive acid-peptic factor and defensive mucosubstance. Inbred female albino rats weighing 100120 g and aged 90ñ 5 days were exposed to either electroshock in grid box at 100 volts (1.2 ms, 72/min, 30 min) or swiming at constant temperature (33(1øC). In chronic groups, exposure to stress continued daily for 21 days. Four hour gastric juice was collected in pylorus ligated rats. Gastric juice volume, acid, pepsin, chloride, mucoprotein and mucoproteoses were estimated along with ulcer index. In addition to gastric function, body weight changes, tissue glycogen (liver, ventricle, skeletal muscle, stomach) and adrenal ascorbic acid levels were also estimated to determine the level of stress. On chronic exposure to electroshock or swimming irrespective of increaseor decrease of gastric juice volume and acidity, there was significant decrease of mucoprotein and mucoproteoses along with increased ulcer index. The results indicated that decrease of mucosubstances in the gastric secretion on exposure to stress plays an important role for the development of lesions in the stomach.

. The present study reveals that apart from adrenaline, the alpha adrenoceptor stimulants noradrenaline and phenylephrine are able to induce pulmonary edema in mice. The ineffectiveness of the alpha adrenoceptor blocker tolazoline in preventing adrenaline induced pulmonary edema and a slight protection by it in noradrenaline and phenylephrine induced pulmonary edema may be due to its less effective alpha blocking property and to its transient action.The involvement of beta adrenoceptor in production of pulmonary edema is ruled out since a powerful beta adrenoceptor stimulant isoprenaline has not been able to induce pulmonary edema. The protective effect of beta blocker propranolol in pulmonary edema induced by adrenoceptor stimulants may be due to its action other than beta blocking property namely local anesthetic action. This hypothesis is supported by the fact that i.v. injection of local anesthetics was found to protect against adrenaline induced pulmonary edema by other workers.

. Pretreatment with L-histidine, precursor of histamine, not only prolonged pentobarbitone sleeping time but also induced sleep in mice treated with a subhypnotic dose of pentobarbitone. These effects of L-histidine were effectively antagonised by prior administration of chlorcyclizine, a H1-receptor blocker. Possible mechanism involved in the potentiating effect of L-histidine on pentobarbitone hypnosis has been discussed.

. The effect of oral pretreatment of some antimicrobial agents was studied on the uterotropic response of immature female rats to a single oral dose of ethinyl oestradiol. Pretreatment with ampicillin, neomycin, metronidazole or pan-amino salicylic acid significantly enhanced the uterotropic response of ethinyl oestradiol. In addition, treatment with ampicillin, neomycin or metronidazole alone significantly increased the uterine wet weight of control rats. However, none of these agents produced conification of the vaginal smear of ovariectomized adult rats. Phenoxymethylpenicillin, tetracycline, rifampicin, chloroquine and streptomycin did not produce any significant change either on the uterotropic response of ethinyl oestradiol or on the uterine weight of control rats.

. A simple cannula for intracerebroventricular (i. c. v.) cannulation in dogs is described with materials easily available in every laboratory. This method is effective, economical and suitable for acute and chronic i. c. v. cannulaton in dogs.

. A flavonoid fraction (XE) extracted from the bark of pterocarpus marsupium Roxb. (Leguminoceae) was studied for the hypoglycaemic activity normal and alloxanised albino rats. The drug XE did not show a consistent effect on normal blood sugar levels but it effectively reversed the alloxan-induced changes in the blood sugar level and the beta-cell population in the pancreas. It also showed a protective effect when it was given prior to alloxan administration. The novel action of drug on the pancreatic beta-cells and absence of acute toxicity may offer a new hope to the diabetics in future.

. Pharmacological, animal toxicity, pharmacokinetic, formulation and stability studies carried out and reported from this Institute in recent years indicated that vasicine, the alkaloid of Adhotoda vasica holds promise for its use as an oxytocic/abortifacient in therapeutics. This report covers the investigations on its clinical pharmacology carried out on 24 human volunteers with 0.5-16 mg dose of vasicine injected iv. in 500 ml saline in 3 hours with the objective of determining any acute human toxicity, tolerance, pharmacological action, any untoward effect and safe dosage range. Vasicine tried upto 16 mg dose on the hospital in-patients on 2nd to 8th day of normal puerperium was well tolerated and showed no undesirable effect in clinical observations, haematological and biochemical investigations and kidney and liver function tests carried out before, during and after vasicine treatment. However, uterus became firm and contracted after vasicine treatment which indicated its effectiveness as an oxytocic.

. Influence of age on the acute toxicity of Sumithion was studied by determining the LD50 values in young and adult rats. LD50 with fiducial limits were found to be 525 mg/kg (257.5-787.7) and 748.7 mg/kg (549.8-950.1) in young and adult rats respectively. Young rats were more susceptible than adult ones. Study on the duration of cholinesterase enzyme inhibitory activity of sumithion at 500 mg/kg given orallty in rats indicated complete inhibition of the enzyme activity at 16th hour which persisted till 8th day. Regeneration of the enzyme activity started by 10th day which tended to increase further.

. Premedication with thiabendazole was found to reduce the duration of tonic extensor phase of electroconvulsive seizures in psychiatric patients undergoing electroconvulsive therapy. However, it did not produce any change in the duration of tonic flexor and clonic phases.