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A Bhardwaj

Publications and source records attributed to A Bhardwaj.

63 records · Page 4Linked to original sources
PubMed1990

Pentobarbital inhibits extracellular release of dopamine in the ischemic striatum.

We examined whether pentobarbital (PB) inhibited the acute extracellular release of dopamine that occurs in the striatum following the onset of ischemic injury in the gerbil model of stroke. The cerebral dialysis technique was employed to monitor striatal extracellular dopamine concentrations before and after carotid artery occlusion while perfusing either a control solution of artificial cerebrospinal fluid (CSF) or a 1 mM solution of pentobarbital in CSF (PB/CSF). During perfusion with CSF, extracellular dopamine increased from a baseline concentration of 0.40 +/- 0.09 (SEM) pmoles/10 minute collection interval to 30.0 +/- 9.0 pmoles/10 minutes after carotid artery occlusion. In contrast, during perfusion with PB/CSF, dopamine levels increased from a baseline of 1.37 +/- 0.3 pmoles/10 minutes to 8.30 +/- 2.6 pmoles/10 minutes; this increase was significantly less than the increase in controls. In animals with established ischemia, repeatedly alternating the perfusion fluid between CSF and PB/CSF demonstrated that dopamine concentrations were significantly increased with CSF alone and decreased with PB/CSF. These findings demonstrate that pentobarbital perfusion either before or following the onset of ischemia inhibits extracellular release of dopamine in the striatum. Inhibition of neurotransmitter release may, in part, be responsible for the protective effect of pentobarbital in ischemic brain injury.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

Striatal L-dopa metabolism studied in vivo in rats with nigrostriatal lesions.

We have used cerebral dialysis to monitor striatal metabolism of exogenously administered L-dopa (L-dihydroxyphenylalanine) in rats with unilateral lesions of the substantia nigra. The concentration of extracellular dopamine (DA) increased in both striata following L-dopa administration but the increase was markedly attenuated in the lesioned striatum. The formation of dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), the major DA metabolites, was also reduced in the lesioned striata following L-dopa administration; however, the reduction was not as great as was that of DA formation. A significant metabolism of exogenous L-dopa to 3-O-methyldopa occurred in both striata. L-dopa administration transiently increased extracellular levels of 5-hydroxyindoleacetic acid (5 HIAA) in both the lesioned and intact striata. These results suggest that the striatum with a reduction in DA nerve terminals is deficient both in the capacity to synthesize DA and in the storage mechanisms necessary to protect the newly synthesized DA from oxidative metabolism.

3,4-Dihydroxyphenylacetic Acid↗
PubMedDate not supplied

Ethanol enhancement of the motor-stimulating effect of nicotine in the rat.

Although ethanol stimulates locomotion in mice, it has been difficult to demonstrate such an action in rats. In contrast, nicotine has been shown to enhance locomotion, including ipsiversive rotation in nigral-lesioned rats. We found no significant effect of ethanol alone on rat rotation at doses of 0.125, 0.50, 1.0, and 2.0 g/kg, IP, during a 30-min observation period. However, there was a dose-dependent effect of ethanol enhancing the rotation induced by nicotine (0.4 mg/kg, SC) given 30 min after the ethanol. The interaction of ethanol and nicotine on locomotion most likely involves the release of dopamine and may be related to the motor abnormalities sometimes seen clinically.

Animals↗
PubMedDate not supplied

Snake bites in the hills of north India.

BACKGROUND: Snake bites are a common cause of morbidity and mortality in the hills. The risk of snake bite is high due to the presence of a huge herpeto fauna flourishing in a favourable climate--low environmental temperature and heavy rainfall. In India, there are 236 species of snakes of which four are dangerously venomous. This study was undertaken to determine the risk factors exposing the population to snake bite and the common types of snakes causing them. METHODS: We studied 243 patients of snake bite over a period of 24 months. All patients were examined for evidence of snake bite and, where possible, the snakes were identified based on description, identification (if the snake was brought) and symptoms of envenomation. RESULTS: Seasonal variation in snake bite was seen, with a peak in the months of August and September. No bites were recorded in December, January and February. Eighty-four per cent of the bites were on the hands and feet (up to the ankle). Bites on the hand were more common in females with a left hand preponderance (3.5 times higher). The age group most affected was between 11 and 40 years (73.7%). Most bites occurred while the person was cutting grass, working in the fields or walking in the hills (75.3%). Snake bites while sleeping were at uncommon sites. Non-poisonous snakes were the most common (90.5%). Kraits caused 60% of bites with envenomation. CONCLUSION: Snake bites occur frequently in the hills of Himachal Pradesh. Although snake bites are a cause for concern, most of them are caused by non-poisonous snakes.

Adolescent↗
PubMedDate not supplied

Does Rota virus infection cause persistent diarrhoea in childhood?

Rota virus is the commonest agent for infectious diarrhoea in childhood. Whether an acute diarrhoea episode due to Rota virus constitutes a risk factor for persistence of diarrhoeal episode has not been well evaluated. This study aimed at evaluating the role of antecedent Rota virus infection in the causation of persistent diarrhoea. One hundred twenty children with acute watery diarrhoea were investigated for evidence of recent Rota virus infection and were followed up for 2 weeks to determine the proportion developing persistent diarrhoea. Rota virus antigen in stool and IgM class antibodies in serum were detected in 33 (27.5%) of the cases, only 2 (6.06%) of whom developed persistent diarrhoea. On the other hand 11.3% children without evidence for antecedent Rota virus infection developed persistent diarrhoea. The prevalence of Rota virus antigen in stools of children who developed persistent diarrhoea was 16.7%. In another group of 25 children with persistent diarrhoea definite evidence for a Rota virus infection was detected in only 2 (8%) cases. It was therefore concluded that antecedent Rota virus infection does not increase the risk for abnormal prolongation of an episode of acute diarrhoea.

Acute Disease↗