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Biomedical subjects

U Banerjee

Publications and source records attributed to U Banerjee.

At least 91 records · Page 5Linked to original sources

Garlic as a natural agent for the treatment of hypertension: a preliminary report.

The major objective of this study was to re-evaluate the effects of garlic on blood pressure with respect to its ability to provoke a decrease in blood pressure and to determine the length of time that this decrease would require. Spontaneously hypertensive rats were given three doses of garlic extract (0.1 ml/kg, 0.25 ml/kg, and 0.5 ml/kg) by oral injection. The blood pressures of these ether-anaesthetized rats were measured immediately before the extract was given, and then 0.5, 2, 4, 6, and 24 h after the extract was given. A blood pressure measurement was also taken at 48 h after extract administration for the 0.5 ml/kg dose. The Gilson Duograph System was used to measure blood pressure by the tail-cuff method. There was a marked decrease in the systolic blood pressure of all of the rats after three doses and the decrease occurred within 30 min in each case. Even though the average decreases for the 0.1 ml/kg and the 0.25 ml/kg doses were calculated as 51,25 mm Hg and 56.25 mm Hg, respectively, these doses were not sufficient to sustain the blood pressure in a normal range for more than 1 or 2 h. The 0.5 ml/kg dose, showing an average decrease of 65.7 mm Hg, was sufficient to provoke a decrease to a normal level and to sustain this decrease for up to 24 h. The results indicate that garlic is effective as a natural agent for the treatment of hypertension.

Animals↗

Comparative assessment of the anticonvulsant activity of some benzodiazepines, phenobarbitone and diphenylhydantoin against maximal electroshock seizures in rats: a time-distribution study.

The anticonvulsant activity of three benzodiazepines (BZDP) and two standard antiepileptic drugs were investigated comparatively against maximal electroshock seizures in rats in a time-distribution study. While phenobarbitone (PHB) and diphenylhydantoin (DPH) gave marked to moderate protection (100%-67%) against tonic seizures up to 6-7 h post-treatment, the BZDP provided significant protection (100%-60%) only up to 1.5 h, with clonazepam being the strongest and diazepam the weakest. Clonic seizures occurred in all treatment groups, whether tonic seizures preceded them or not, but their duration was longer in the DPH and PHB groups than in the BZDP groups. Total seizure durations were often significantly reduced in the BZDP groups, notably with clonazepam, whereas it was invariably longer in the DPH and PHB groups when compared with the vehicle treated controls. The BZDP treated rats generally required longer time to recover from postictal coma, the effect being dose-related. the DPH and PHB treated rats needed longer recovery time when the treatment-test interval was 18-20 h.

Animals↗

Comparative study of retrograde amnesia in rats on active and passive avoidance tasks and spontaneous recovery of memory.

Naive and pretrained rats were trained in two active avoidance paradigms using a pole-climbing box and in a single-trial passive avoidance task using a T-maze. They were then subjected to amnestic treatments with electroshock, leptazol, pentobarbitone, or ether anesthesia. Single retention tests were given at 20-24, 44-48, or 68-96 h posttreatment. Electroshock and leptazol seizures produced retrograde amnesia in all three paradigms, provided that seizures were maximal and retention was tested before 48 h. Prior treatment with anticonvulsant drugs prevented amnesia. Ether and pentobarbitone anesthesia failed to produce amnesia in all three tasks. A trend of recovery from amnesia was observed in the electroshock and leptazol groups when tested for retention 48-96 h posttreatment. On the other hand, the non-amnesic control, pentobarbitone, and ether groups showed signs of forgetting at these longer intervals. Consolidation failure and/or retrieval block was surmised to be the cause of amnesia; recovery was the possible result of removing the block.

Amnesia↗

The temporal dimensions of anticonvulsant action of some newer benzodiazepines against metrazol induced seizures in mice and rats.

In a time-distribution study, the anticonvulsant effects of four benzodiazepine compounds were compared with those of three standard antiepileptics against metrazol-induced seizures in mice and rats. Ethosuximide and trimethadione had the shortest duration of action in mice, but protected the rats up to 6 hr. Phenobarbitone, diazepam, flurazepam and nitrazepam protected the mice up to 12 hr, but the rats were effectively protected only up to 3-4 hr. Clonazepam, the most potent and effective agent, protected the mice from clonic-tonic seizures up to 18-20 hr and the rats up to 6-7 hr. Comparison of the PD50 from clonic seizure at the peak-effect hours revealed that the benzodiazepines were 16 to 96 times more potent than phenobarbitone on a molar basis, while phenobarbitone itself was 12 to 26 times more potent than ethosuximide and trimethadione. Tonic seizures and mortality were largely suppressed by all drugs until 18-20 hr in mice and 6-7 hr in rats. Seizure latency and mortality patterns varied from drug to drug but not in a dose-dependent manner.

Animals↗

Secondary reinforcement property of a stimulus paired with morphine administration in the rat.

Rats learned to run to the correct arm of a Y-maze. Correct responses were reinforced with morphine injection paired with a conditional tone stimulus. After the maze response was well established, extinction trials were run. During extinction half of the animals received neither morphine nor tone as a consequence of a correct response, while the other half received the tone but no morphine. Rats receiving the tone during extinction required significantly more trials to reach the extinction criteria than rats not receiving tone presentations. Extinction with the tone also facilitated relearning of the maze response. The results support the view that morphone is a potent reinforcer, and that stimuli paired with morphine administration acquire the properties of a secondary reinforcer.

Acoustic Stimulation↗

Conditioned learning in young rats born of drug-addicted parents and raised on addictive drugs.

Ratlings born of six drug-addicted and a control group of parent rats were raised under the influence of the same drugs administered in drinking water. They were trained in a conditioned avoidance paradigm (CAR) from the 7th week when the drugs were withdrawn except in two subgroups of flurazepam and morphine. The growth rate was not appreciably impaired except for temporary slowness in morphine and alcohol-raised rats; it was faster in phenobarbitone and meprobamate-raised rats. The CAR-acquisition rates of the treatment groups were quite close and parallel to that of the controls except for the morphine, meprobamate, medazepam and the two drug-trained subgroups; whereas, the rats raised on low-dose morphine showed a faster than control acquisition rate. No evidence of state-dependent learning was obtained from this study.

Animals↗

Conditioned avoidance behavior in pretrained rats intermittently treated with addictive drugs.

Rats pretrained in a conditioned avoidance (CAR) paradigm were put on eight potentially addictive drugs in drinking water at two dose levels each. Fluid intake and body weight, monitored during the drugged (addiction) and nondrugged (withdrawal) states, showed drug/dose-dependent fluctuations in most groups. Extinction and relearning trials were spread over both drug and nondrug phases. CAR-performance generally deteriorated in the early drug phase but improved to near normalcy during the late drug and withdrawal phases in all groups except for alcohol and barbiturate-treated one. Excluding amphetamine, low-dose morphine and phenobarbital groups, substantial extinction of CAR occurred during the drug phase only; these three groups, as well as the high-dose alcohol, barbiturates and medazepam ones, showed extinction during the nondrug phase also. The rate and extent of a second-order relearning neither differed significantly between the groups nor was truly contingent upon prior extinction. These results are discussed in the light of state-dependent learning, comparing them with those from another series of rats primarily trained under the influence of these addictive drugs.

Amphetamine↗

Temperature responses and other effects of 5-hydroxytryptophan and 5-hydroxytryptamine when acting from the liquor space in unanaesthetized rabbits.

1. In unanaesthetized rabbits 5-hydroxytryptophan (5-HTP) and 5-hydroxytryptamine (5-HT) were injected into the cisterna magna or into the cannulated left lateral cerebral ventricle while rectal temperature was recorded.2. 5-HTP injected intracisternally in a dose of 1.5-3 mg produced a fall in temperature often followed by a rise beyond the pre-injection level. With 6 mg the main effect was a rise in temperature. The intraventricular injection of 1-2 mg 5-HTP usually produced a fall followed by a rise.3. 5-HT injected intracisternally in a dose of 0.2 mg produced a fall in temperature similar to that produced with this dose injected intraventricularly. Following an intracisternal injection of 1-4 mg 5-HT there was either a fall, or a fall followed by a rise, but in a few experiments the effect consisted mainly of a rise in temperature.4. Additional effects regularly observed with these injections were tachypnoea, ear twitching, rapid movements of the vibrissae, shaking of the head, wiping and scratching movements, ataxia, nodding and sideways movements of the head and long-lasting catalepsy.5. The sites where 5-HTP and 5-HT act when producing the temperature responses and the various behavioural effects are discussed.

5-Hydroxytryptophan↗