Key Word Index: P-Sitosterol; Anti-inflammatory; Antipyretic. AbstractThe anti-inflammatory and antipyre-

Summary1. Studies on the urine outflow, blood ADH concentration and electrolyte excretion were carried out in a-chloralose anaesthetized hydrated dogs; the agonists and antagonists of specific cholinoceptors and adrenoceptors were injected by the intracerebroventricular technique, to delineate the role of the C.N.S. receptors in the control of ADH secretion. 2. Central injection of acetylcholine elicited a dose-dependent antidiuretic response which was associated with an increase in the blood ADH titre. Central atropinization partially blocked the antidiuretic response. The remaining antidiuretic response was reversed to a diuretic one by further pretreatment with phenoxybenzamine. The diuretic response thus obtained could be blocked by propranolol. 3. The a-adrenoceptor agonists, phenylephrine and noradrenaline, induced dose-dependent antidiuretic responses with a concomitant rise in blood ADH concentration. Their effect could be blocked by pretreatment centrally with phenoxybenzamine. Low doses of adrenaline induced a diuretic response and a decrease in blood ADH concentration, higher doses elicited a dose-dependent antidiuretic response and increase in the titre of ADH in blood. Central phenoxybenzamine pretreatment reversed the antidiuretic effect of high doses of adrenaline to a diuretic effect which could be blocked by propranolol. 4. Isoprenaline elicited a dose-dependent diuretic response and a decrease in blood ADH titre and propranolol competitively blocked the effect of isoprenaline.5. It is concluded that central muscarinic cholinoceptors and the a-adrenoceptors are concerned in the release of ADH, whereas the /3-adrenoceptors are concerned with inhibition of ADH release.Methods Sixty-two mongrel dogs of either sex, weighing between 10 to 15 kg, were employed in the study. Animals were fasted for 24 hours but were allowed water ad lib. The dogs were anaesthetized with a warm solution of 1% a-chloralose in 09% NaCl solution (10 ml/kg) administered intravenously. The diuresis was produced by intravenous infusion of an iso-osmotic solution containing 1-8% dextrose and 0-14% sodium chloride and to maintain anaesthesia 005% a-chloralose was added to the solution. The solution was initially infused at the rate of 15 to 4-0 ml/min till a total of 50 ml/kg had been delivered. Thereafter, the rate of infusion was adjusted to exceed slightly the rate of urine flow in order to maintain

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SUMMARY Serotonin (5-hydroxytryptamine, 5-HT) is implicated in the pathogenesis of migraine; however, its role in tension headache has not yet been studied. The uptake of 5-HT by platelets in patients of tension headache was significantly higher compared with migraineurs as well as controls. The basal platelet 5-HT levels did not show a significant difference. The study implicates the role of serotonin in tension headache.The involvement of 5-HT in migraine is well established. A decrease in basal platelet 5-HT as well as a reduced uptake of 5-HT by the platelets has been reported.' 4 However, platelet 5-HT uptake in tension headache has not so far been explored. It has been suggested that migraine (classical as well as common), tension-vascular and tension headache are a continuum of the same pathophysiology. The precise margins of these clinical entities are elusive.5 Hence it was considered appropriate to study the role of serotonin in tension headache. This appears to be the first report of platelet serotonin uptake in tension headache. Patients and methodsTwenty patients with tension headache, attending the neurology out-patients department, were included in the study. The mean age was 29 5 with a range of 14 to 45 years and male:female ratio was 1:3. Nineteen patients of migraine were also studied. The mean age was 30 7 years (range 16 to 50 years) and male:female ratio 1:1 7. The diagnosis of migraine was based on the criteria given by the World Federation of Neurology6 whereas tension headache was diagnosed according to the following criteria based on a modification of those suggested by the ad hoc committee of the headache group.7 "Patients with headache lasting for 24 hours, non localised, dull ache described as heaviness or a band being tightened around the head without any nausea or vomiting, precipitated by tension and stressful situations, relieved by sleep or tranquilisers and no relief with ergot alkaloids". Fifteen age and sex matched controls comprising unpaid healthy volunteers taken from hospital staff and patients suffering from neurological disorders not likely to affect 5-HT metabolism (such as myopathy, peripheral neuropathy and motor neuron disease) were also included.Patients suffering from hypertension and ischaemic heart disease were excluded. None of those included in the study was taking drugs (analgesics, antidepressants etc.) and food items (banana, tomato, pineapple, nuts, cheese etc) known to effect 5-HT metabolism, for 7 days prior to collection of blood samples.Blood was collected (9 ml) by venepuncture from the median cubital vein at 9 00 am using a plastic syringe with a 21 gauge needle. It was immediately transferred to plastic tubes, containing I ml of 3-8% sodium citrate, and kept in iced containers.Platelet rich plasma (PRP) was prepared by centrifugation according to the method of Born and Gillson.8 All glass equipment used in the experiments was coated with silicone. Platelet counts in PRP were done in a Neubauer haemocytometer at a dilution of 1 in 20. Basal platelet ...