Biomedical subjects

B A Kumar

Publications and source records attributed to B A Kumar.

4 recordsLinked to original sources

PubMed1988

CGS 8216, a benzodiazepine receptor antagonist, enhances learning and memory in mice.

Mice pretreated with the benzodiazepine antagonist, CGS 8216 (2.5, 10, or 40 mg/kg, i.p.) learned a T-maze discrimination to a fixed performance criterion more rapidly than vehicle-treated mice. In retention tests conducted one week later, the drug-treated groups had better first-trial recall and greater difficulty reversing the previously trained maze habit when compared with controls, suggesting improved memory for the previously trained maze habit. The enhanced acquisition and retention following CGS 8216 was similar to that observed previously with another benzodiazepine antagonist, flumazenil (Ro 15-1788). It is postulated that CGS 8216 and flumazenil could act at benzodiazepine receptors to antagonize a tonic inhibitory influence of endogenous, diazepam-like, benzodiazepine receptor ligands on memory processes.

Animals↗

PubMed1988

Feeding and macronutrient selection patterns in rats: adrenalectomy and chronic corticosterone replacement.

To analyze further the role of corticosterone (CORT) in the control of feeding behavior, we examined the impact of adrenalectomy (ADX) and chronic CORT implants on the food intake and macronutrient self-selection patterns of adult male rats at different periods of the diurnal cycle. Consistent with a separate study of acute CORT injection in ADX rats (Kumar and Leibowitz, 1988), the present findings indicate that ADX significantly attenuated the rats' daily (24 hr) ingestion of all three macronutrients, namely, protein, carbohydrate and fat. However, food intake in the dark cycle, specifically during the first few hours after dark onset, was significantly more affected (-70%) than feeding in the later dark and light periods (-25%). Moreover, during this early dark time when circulating CORT level normally peaks, ADX appeared to have its strongest suppressive effect on carbohydrate ingestion. Chronic subcutaneous CORT implants in the ADX animals reversed these effects of surgery and generally restored the rats' eating patterns to that of the cholesterol-implanted SHAM animals. These findings suggest that CORT exerts a decisive influence on caloric intake, on the diurnal pattern of feeding, and on appetite for specific macronutrients. The impact of CORT on carbohydrate intake is apparent specifically during the active eating period, particularly at dark onset when endogenous CORT levels normally peak and carbohydrate is exhibited as the preferred macronutrient.

Activity Cycles↗

PubMed1988

Impact of acute corticosterone administration on feeding and macronutrient self-selection patterns.

Food intake, body weight, and meal patterns in rats are known to be specifically influenced by circulating corticosterone (CORT). The present study examined, in Sprague-Dawley rats, the role of CORT in the regulation of caloric intake and choice of macronutrients during specific periods of the light-dark cycle. Adrenalectomy (ADX) significantly attenuated the ingestion of all three macronutrients, namely, protein, carbohydrate, and fat, in different test periods of the light-dark cycle. This deficit was significantly stronger just before or during the early dark hours, compared with the light period, and it was immediately CORT reversible. During this same early dark period, the stimulatory effect of CORT (0.5 or 2.0 mg/kg sc) on total food intake in ADX animals was also significantly stronger than during the light period. At this time, the CORT-injected ADX animals consumed an even greater amount of total food intake than did the vehicle-injected sham-operated animals and showed a significant preference for carbohydrate, as opposed to no change or a decline in preference for protein or fat. These findings, in light of other evidence, suggest that CORT ensures and stabilizes the ingestion of all three macronutrients but, in particular, stimulates carbohydrate ingestion during the important feeding period at the dark onset when CORT levels normally peak. It is proposed that CORT may provide a critical signal, in conjunction with hypothalamic neurotransmitter systems, in the behavioral and metabolic regulation of body energy balance.

Adrenalectomy↗

PubMedDate not supplied

[Bilateral traumatic subdural hematomas].

The authors studied 57 verified cases of bilateral traumatic subdural hematomas (BTSH) 36 of which were acute, 4 subacute, and 17 chronic. The patient's ages ranged from 15 to 84 years. The clinical picture of BTSH is made up of general cerebral, primary-focal, and dislocation symptoms. Computerized tomography, serial cerebral angiography, and trephinations formed on both sides help in detection of BTSH. Simultaneous opening of the dura mater on both sides with slow evacuation of the contents of the hematomas is an important stage of surgical intervention in BTSH.

Accidents, Home↗