The head shaking nystagmus.

The head shaking nystagmus is a sign of vestibular assymmetry. Its detection is simple office test useful for screening the patients with vertigo and dysequilibrium. Its nature defies its recording with electro-oculography and is simply observed under Frenzel's glasses. The direction of nystagmus is persistently directed away from the site of lesion and is not influenced by the compensatory adjustments. It is transient, rotatory and repeatable in nature. Its reliability is limited in face of the difficulty in its recognition. In presence of strong spontaneous nystagmus in the same face, it is not recognised easily. In the present study, its validity in peripheral disorders was 49.27% and 14% in central cases. There are limitations In earring out this test in situations of railed intracranial the tension, hence, its use in the latter cases is limited.

Novel appearance of placental nuclear monoamine oxidase: biochemical and histochemical evidence for hyperserotonomic state in preeclampsia-eclampsia.

OBJECTIVE: The aim of this study was to explore the relevance of placental monoamine oxidase at the subcellular level in the etiology of the hyperserotonomic state in preeclampsia-eclampsia. STUDY DESIGN: The study was conducted on placentas from 20 normal pregnant women and 25 women with varied severity of preeclampsia-eclampsia. Placental serotonin and subcellular monoamine oxidase activity were determined. Histochemical localization of monoamine oxidase was done in placental sections and cell isolates. RESULTS: Placental serotonin increases with severity (rsystolic 0.84, rdiastolic 0.83) and monoamine oxidase decreases (rsystolic 0.86, rdiastolic 0.79). Placental monoamine oxidase showed marked changes in preeclampsia-eclampsia. Histochemical localization of monoamine oxidase showed diffused low activity evenly throughout the cytoplasm and nucleus of the syncytiotrophoblastic cells in preeclampsia-eclampsia; in contrast, normal placenta showed high activity in the cytoplasm without any activity in the nucleus of syncytiotrophoblastic cells. Detection of monoamine oxidase activity in nuclei of the placenta in preeclampsia-eclampsia is a novel finding. Monoamine oxidase activity at the subcellular level further strengthens this observation. A severity-dependent decrease was present in the nuclei of placentas with preeclampsia-eclampsia. The use of specific substrates and inhibitors revealed the presence of monoamine oxidase in mitochondria and nucleus. CONCLUSION: The study delineates an impaired catabolism of placental serotonin in preeclampsia-eclampsia. The novel appearance of monoamine oxidase in nuclei in proximity to its normal site and low activity resulting in a hyperserotonomic state may lead to preeclampsia-eclampsia.

A study of free radicals and scavenging enzyme in tonsillitis.

The present study is a comparison of malonaldialdehyde (MDA) level and superoxide dismutase (SOD) activity between controls and in tonsillitis patients of different degree before (pre) and after (post) surgery (tonsillectomy). The SOD activity increases in pretonsillectomy cases according to severity of disease and there is a rise in MDA level whereas after tonsillectomy although the increase in SOD is marginal but MDA declines sharply as compared to pretonsillectomy patients indicating that the SOD exerts its protective effect after surgery.

A study of effects of putative neurotransmitters injected into the lateral cerebral ventricle of man.

1. The study was carried out in adult patients having normal cardiovascular reflexes and no brain stem lesions. They were exposed to ambient temperature of 72-74 degrees F. Injections of agonists and antagonists of receptors were made into the lateral cerebral ventricles of these patients through diagnostic burr hole in the skull. 2. Noradrenaline, adrenaline and dopamine evoked hypotension and bradycardia. While the core temperature was reduced by nor-adrenaline and adrenaline, dopamine evoked hyperthermia. Isoprenaline elicited hypertension, tachycardia and hyperthermia. Opposite cardiovascular and thermal effects were observed with blockade of alpha 1-, beta-and dopamine receptors with prazosin, propranolol and haloperidol respectively. 3. Injection of 5-hydroxytryptamine resulted in hypertension, tachycardia and hyperthermia but hypotension, bradycardia and hypothermia were seen with methysergide. 4. Similarly, carbachol injection caused initial excitatory followed by inhibitory cardiovascular responses. These were associated with hypothermia. On the contrary atropine per se elicited hypertension, tachycardia and hyperthermia. 5. Thus, alpha 1- and beta-adrenoceptors, dopaminergic, serotonergic and muscarinic cholinergic receptors are present in human brain which appear to modulate cardiovascular activity and core temperature.

Protection against gastric ulcer by verapamil.

The effect of verapamil, a calcium channel blocker, was studied against stress (cold restraint), aspirin and pylorus ligation induced gastric ulcers in rats. Verapamil inhibited ulcerogenic response and ulcer index in all the three types of ulcers. Verapamil also decreased total and free gastric acidity without changing gastric secretory volume.

Role of histamine receptor in mesencephalic nucleus dorsalis raphe in cardiovascular regulation.

The effects of microinjection of histamine and its antagonists into mesencephalic nucleus dorsalis raphe, were investigated on mean arterial pressure and heart rate in cats to elucidate the nature and role of histaminergic receptors in cardiovascular regulation. Microinjection of histamine (5 and 10 micrograms) into nucleus dorsalis raphe elicited both inhibitory and excitatory cardiovascular responses respectively. On the other hand, microinjection of H2-receptor blocker, cimetidine (10 micrograms) resulted in hypertension and tachycardia while H1-receptor antagonist, mepyramine (10 micrograms) microinjection evoked hypotension and bradycardia. Furthermore, local pretreatment with cimetidine and mepyramine blocked the inhibitory and excitatory cardiovascular responses of graded doses of histamine microinjection. These H1 and H2 receptors are localized in nucleus dorsalis raphe since microinjection of histamine into adjoining neural structures did not evoke any cardiovascular change. Furthermore, both the inhibitory and excitatory cardiovascular responses to histamine microinjection could not be observed in animals with spinal cord transection and in animals pretreated with p-chlorophenylalanine while they could be observed in bilateral cervical vagotomized animals. Thus, it appears that these cardiovascular responses to microinjection of histamine into nucleus dorsalis raphe, are due to modulation of serotonergic bulbospinal influence on sympathetic preganglionic neurones in the spinal cord. Moreover, the excitatory cardiovascular responses of high dose of histamine (10 micrograms) seem to result from a local release of noradrenaline since they were blocked by prior microinjection of guanethidine and piperoxan into nucleus dorsalis raphe. A release of noradrenaline in turn, modulates the activity of the neurones of the nucleus by acting on alpha adrenoceptors and thereby alters the activity of sympathetic preganglionic neurones.(ABSTRACT TRUNCATED AT 250 WORDS)

Presence of opioid receptors in mesencephalic nucleus dorsalis raphe concerned in cardiovascular regulation in cats.

The effects of microinjection of opioid receptor agonist and antagonist into mesencephalic nucleus dorsalis raphe, were studied on mean arterial pressure and heart rate to elucidate the nature and role of these opioid receptors in cardiovascular regulation. Microinjection of morphine (5 micrograms and 10 micrograms) into nucleus dorsalis raphe elicited both inhibitory and excitatory cardiovascular responses respectively, while microinjection of opioid receptor antagonist, naloxone (10 micrograms) failed to produce any significant cardiovascular responses. However, local pretreatment with naloxone blocked both inhibitory and excitatory responses of graded doses of morphine. These opioid receptors seem to be localised in the neurons of the nucleus since microinjection of morphine into neural structures adjoining nucleus dorsalis raphe failed to induce any cardiovascular responses. Furthermore, the dose or morphine (2 micrograms) which was ineffective when microinjected into nucleus dorsalis raphe, produced inhibitory cardiovascular responses after pretreatment with LM5008, a 5-HT uptake blocker. Similarly, the excitatory cardiovascular responses of morphine microinjection were blocked by spinal cord transection (C1) and p-CPA, guanethidine and piperoxan pretreatments, while bilateral cervical vagotomy failed to do so. Thus, it is likely that the inhibitory cardiovascular responses of morphine are mediated directly through stimulation of opioid receptors present in the neurons of nucleus dorsalis raphe while the excitatory responses to higher dose of morphine, appear to be due to a release of noradrenaline which in turn modulates the activity of neurons by acting on alpha adrenoceptors.

Cardiovascular responses elicited by microinjection of monoamines into mesencephalic nucleus dorsalis raphe in cats.

The effect of monoaminergic agonists and antagonists microinjected into mesencephalic nucleus dorsalis raphe has been studied on blood pressure and heart rate to elucidate the nature and role of these monoaminergic receptors in cardiovascular regulation. Microinjection of monoamines, noradrenaline, phenylephrine and 5-hydroxytryptamine (5-HT) into nucleus dorsalis raphe elicited hypertension and tachycardia which could be blocked by local pretreatment with piperoxan (an alpha-adrenoceptor blocker) and methysergide (a 5-HT receptor blocker) respectively. However, isoprenaline microinjections failed to evoke any response. Bilateral vagotomy did not prevent these cardiovascular responses evoked by monoamines microinjection, while cervical spinal cord (C1) transection with bilateral vagotomy prevented these responses. These monoaminergic receptors seem to be localized in nucleus dorsalis raphe since microinjection of monoamines into neural structures adjoining nucleus dorsalis raphe, failed to induce any cardiovascular response. Monoaminergic receptors are present in nucleus dorsalis raphe which modulate cardiovascular activity by influencing sympathetic preganglionic neurons in the intermediolateral columns of the spinal cord.

Serotonin in toxaemia of pregnancy.

Serotonin (5-hydroxytryptamine) contents of maternal blood, fetal cord blood, and placenta from thirty-five patients with toxaemia of pregnancy and forty normal pregnant subjects were estimated. Placental monoamine oxidase activity from ten normal and ten toxaemic cases were also estimated. An increased content and uptake of serotonin by platelets in maternal blood from toxaemic patients were observed and there was a concomitant reduction in platelet count. Raised levels of serotonin and a decrease in monoamine oxidase levels were observed in placentas of the toxaemic group. The levels of serotonin in fetal cord blood were significantly higher than those in normal maternal blood. It is suggested that the fetus could be the source of increased serotonin in this syndrome, due to the decrease in monoamine oxidase activity in the toxaemic placenta. An abnormality in indole amine metabolism may contribute to the pathology associated with toxaemia of pregnancy.

Presence of cholinoceptors in mesencephalic raphe nuclei concerned in thermoregulation in rabbits.

The thermal effects of cholinomimetics and cholinoceptor blocking agents microinjected into mesencephalic nucleus raphe medianus (NRM) were investigated in rabbits to determine the nature and role of these cholinoceptors in thermoregulation. Microinjection of cholinoceptor agonists, carbachol and pilocarpine, into NRM resulted in significant hyperthermia which could be blocked by local pretreatment with chlorisondamine (a nicotinic receptor blocker) as well as by ethybenztropine (a muscarinic receptor blocker). Intracerebroventricular pretreatment with LM 5008 (serotonin reuptake blocker) significantly inhibited the carbachol-induced hyperthermia. Both nicotinic and muscarinic cholinoceptors are present in mesencephalic NRM which may be involved in thermoregulation in rabbits. Activation of these cholinoceptors in NRM results in hyperthermia which seems to be due to an inhibition of a serotonin sensitive hypothalamic heat loss mechanism.

Cardiovascular responses elicited by microinjection of cholinergic agents into nucleus dorsalis raphe in cats.

The effect of cholinomimetics and cholinoceptor blocking agents microinjected into nucleus dorsalis raphe (NDR) has been studied on heart rate and blood pressure to identify the nature and role of these cholinoceptors in cardiovascular regulation. Microinjection of the cholinoceptor agonists, pilocarpine and carbachol into NDR elicited bradycardia and hypotension accompanied by salivation which could be blocked by local pretreatment with ethybenztropine (a muscarinic receptor blocker), but not by chlorisondamine (a nicotinic receptor blocker). Pretreatment with atropine methylnitrate (i.v.), which blocks only peripheral muscarinic receptors, did not prevent these cardiovascular responses evoked by carbachol microinjection. These cholinergic receptors seem to be localized in NDR since, microinjection of carbachol into neural structures adjoining NDR, failed to induce any cardiovascular responses. Muscarinic cholinoceptors are present in NDR which modulate cardiovascular activity by influencing sympathetic preganglionic neurons in the intermediolateral columns of the spinal cord.