The Nomenclature Committee of the Serotonin Club now recognizes four distinct types 5-hvdroxvtrvptamine (5-HT: serotonin) receptors called 5-HTI. 5-HT2. 5-HT3 and 5-HT4 . There is-now good evidence that the 5-HT1; and 5-HT2 receptors areheterogeneous and have several subtypes.Besides these receptors, there is another category of the so-called "orphan" receptors which await definitive classification. Two such kinds of receptors are collectively known as 5-HT1-like receptors; in order to distinguish between them they are sometimes denoted as 5-HT1X and 5-HT1Y, which mediate vasoconstriction (predominantly, but not exclusively, of cephalic vessels) and vasodilatation, respectively. Vasoconstriction in most other vessels is usually mediated by 5HT2A receptors. Injection of 5-HT and several other agonists at 5-HT1 -like receptors redistribute carotid blood flow so that arteriovenous anastomotic blood flow decreases despite, sometimes, an increase in tissue (arteriolar) blood Row. There is now good evidence that agonists at 'constrictor' 5HT1 -like (5-HT1x) receptors have the ability to abort migraine attacks. The other 5-HT receptors, including the 5-HT2A, 5-HT2c and 5-HT3 receptors, do not seem to play an important role in the antimigraine action of the currently available drugs.

The effect of organophosphorous compounds on memory, both immediate and recent, were studied in the rat. Following acute oral or chronic inhalational exposure to methylparathion (MPT), rats were tested in a complex maze. Acute oral exposure was found to compromise recent memory function but not immediate memory function. After chronic inhalational exposure, no significant alterations in either recent or immediate memory functions were detected. The negative findings of this study may be genuine or may necessitate modifications in the memory task to more sensitively identify deficits. The modifications suggested are limitations of the maze-familiarization period, and use of a spaced-learning model instead of a massed-learning task model.

Drug utilisation pattern and incidence of reactions of commonly prescribed antiepileptic drugs in a group of patients are analysed. Incidence of reactions in this group is 27.4%. Most commonly prescribed drugs are phenobarbitone, phenytoin and carbamazepine. Number of drugs prescribed, age of patients and dose of drugs are the factors influencing the occurrence of reactions. Major reactions to phenobarbitone are related to central nervous system such as headache, drowsiness and giddiness. Gum hyperplasia is the commonest reaction reported by patients on phenytoin therapy. Cognltive functions are influenced by both phenobarbitone and phenytoin. Ataxia, nystagmus and slurred speech are the disturbing reactions caused by phenytoin.

Fifty unmarried girls suffering with primary dysmenorrhoea, participated in a double-blind, parallel trial of nifedipine versus placebo. The efficacy of the nifedipine/placebo was assessed by measuring the intensity of pain, the degree of pain relief, the necessity of a supplementary analgesic and the extent to which drugs enable the patients to continue their daily activities during each dysmenorrhoeic cycle. In this study nifedipine was found to be significantly superior as compared to the placebo. Among severely incapacitated group more number of nifedipine treated patients(11 /1 6) were able to continue their daily activities as compared to placebo group (4/13). Only 3 girls experienced few side effects.

High dose chandonium iodide, 200, 250,300,350 and 400 'g/kg was randomly administered to 45 ASA physical status I-II patients for muscle relaxation during general and gynaecological surgery. Neuromuscular blockade was quantitated with ulnar nerve stimulation (myotest) and also assessed clinically. Time to onset of muscle relaxation, apnoea, endotracheal intubation conditions, duration of neuromuscular blockade, and haemodynamic effects of chandonium at each dose were evaluated and compared. Time to onset of muscular relaxation decreased from 72.3(15.5 to 38.0ñ 15.3 second as the chandonium dose was increased from 200 to 400 'g/kg (P< 0.01). Recovery of limb movements and hand grip after extubation was not altered clinically or statistically. However, increased recovery time to head lift for 5 seconds from 12.7ñ 9.6 to 20.1ñ 11.2 min was seen with higher dosage of chandonium. No significant haemodynamic differences between 250 and 400 'g/kg groups were observed. High doses of chandonium, may, therefore, be a useful alternative to succinylcholine to achieve similar quantitative as well as qualitative neuromuscular blockade for intubation conditions.

ST-93 induced significant diuresis in rats. Dose-dependent effects were observed in urine volume and electrolyte excretion. Dose-related natriuretic and chloruretic activities were noticed. Prazosin and yohimbine significantly antagonised diuresis of ST- 93, while propranolol, cimetidine, cyproheptadine, naloxone and bicuculline had no such effect. The data suggest the possible involvement of both alpha-l and alpha-2 adrenoceptors in the diuretic effect of ST 93 in rats.

Effect of Azadirachta indica (A.indica) leaf extract on inflammatory oedema induced by chemical mediators (5-HT, histamine, bradykinin and PGE1) was studied to find out its possible mechanism of reported antiinflammatory effect against carrageenin induced rat hind paw oedema. The test material showed significant antiinflammatory effect against 5-HT and PGE1 induced inflammation but not on the inflammation induced by histamine and bradvkinin. Median effective doses of A.indica for 5-HT and PGE1 induced oedema were 1.17g and 930 mg/ kg respectively. The result suggests that A.indica extract's antiinflammatory effect may be due to antagonism of the deleterious effect of 5-HT and PGE1 on blood vessels.

Reproductive studies of an antiasthmatic compound, 7,8,9-1 0- tetrahydroazepino (2,1 -b)-quinazoline- 12 (6H)-one were carried out as a prelude to clinical trials. Compound was devoid of any adverse effect on male and female fertility. There was no specific effect of treatment on gestation length. litter size and birth weight of pups in teratogenic studies in rats and rabbits. Prenatal and postnatal studies in rats revealed no untoward effect The compound seems to be free from any adverse effect on reproductive system

The rats were challenged with 0.5, 1, 2 or 3 mg/kg cadmium (i.p) to observe its effect on the serum levels of protein bound hexose (PBH). Dose dependent increase was found in the levels of PBH, 48 hrs post cadmium administration. Serum levels of PBH might be useful for monitoring the cadmium toxicity with known cadmium exposure.

Abana, an ayurvedic formulation was studied in dogs (n=l9) for its anti-arrhythmic activity. After prophylactic oral administration it produced slight reduction in the duration of aconitine induced atrial flutter/fibrillation but no effect was observed on atrial/ventricular rates, Curative effect was not seen against coronary artery ligation induced ventricular tachycardia.

After 15 days of single daily oral administration of tricyclic antidepressants (imipramine, desipramine 10 mg/kg each, amitriptyline, nortriptyline 7.5 mg/kg each and protriptyline 5 mgikg) in rabbits, reduced the minimum effective dose of gallamine to elicit head drop. Potentiating effect persisted significantly up to 24 hour. Similarly double the doses of these tricyclic antidepressants reduced the quantity of gallamine significantly up to 48 h. and total recovery from the effect appeared after 72 h. It is suggested that the potentiation of the action of gallamine by tricyclic antidepressants may be of clinical importance in patients especially if any of these tricyclic antidepressants has been taken shortly before.

The present study was undertaken to evaluate the role of felodipine, a newer calcium antagonist, in the management of congestive heart failure. Sixteen patients of congestive heart failure due to different causes received felodipine for 2 weeks. Ejection fraction, oxygen uptake and exercise capacity were evaluated after 2 weeks. Adverse reactions were noted. Felodipine therapy resulted in increased ejection fraction, oxygen uptake and exercise capacity. The drug was well tolerated. It is concluded that felodipine may be useful in the management of congestive heart failure.

Patients compliance to insulin was investigated in 45 Zambian diabetic patients. Non-compliance was found in 31 of them. 25 patients were underdosing while 6 were overdosing themselves. The major reasons for it were inability to understand the usage of syringes due to freauent changes in insulin strenaths and type of syringes; and deliberate underdosing for fear of interrupted in supply.