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H STEINBERG

Publications and source records attributed to H STEINBERG.

At least 19 recordsLinked to original sources
PubMed1963

Effects of a single experience on subsequent reactions to drugs.

The activity of rats in an unfamiliar environment was studied in order to determine how far their reactions to an amphetamine-barbiturate mixture depended on whether or not they had been under the influence of this mixture while exposed to the same environment once before. The environment consisted of a Y-shaped runway, and the activity studied was the number of entries into the arms of the Y during a three-minute trial; the two trials took place three days apart. At the first trial the drug mixture practically doubled activity. At the second trial rats which had been under the influence of the drug mixture at the first trial were again made more active by the drug mixture, but the drug mixture did not increase the activity of rats which had received only saline at the first trial. These results showed that a single brief exposure to an unfamiliar environment can markedly affect subsequent reactions to drugs, and interactions of this kind may have to be taken into account when it is desired to use animals repeatedly in tests of the action of drugs on behaviour. The drug mixture also produced ataxia which was assessed quantitatively by measuring the variability of the "splay" of the rats' footprints; ataxia was unaffected by previous experience.

Amobarbital↗
PubMed1963

MUTUAL POTENTIATION OF AMPHETAMINE AND AMYLOBARBITONE MEASURED BY ACTIVITY IN RATS.

Dose/response relations have been analysed for the actions of amphetamine-barbiturate mixtures on exploratory activity and ataxia in rats. Amphetamine sulphate and amylobarbitone sodium were studied separately and together (in a constant ratio of 1:20) in doses which ranged from those producing no effect to those which incapacitated the animals. Dexamphetamine and amylobarbitone were similarly studied in a ratio of 1:6.5; this corresponds to the ratio of a commercial preparation, Drinamyl. The results showed that mixtures could stimulate exploratory activity and their maximal effects were much greater than the effects produced by any dose of the separate drugs. The maximal effect with the first dose-ratio included conspicuous ataxia, but the maximal effect with the second ratio did not. Further experiments in which the dose of one drug was held constant and that of the other was varied showed that maximal effects on activity could be obtained with mixtures of dexamphetamine and amylobarbitone. Equivalent effects could be obtained both with relatively small and with relatively large amounts of the two drugs, in varying ratios; some constituent doses of the individual drugs were found to be optimal; whether the mixture effect was accompanied by ataxia depended largely on the constituent amount of barbiturate. For practical purposes mixtures producing maximal effects on activity with the smallest amounts of both drugs and not accompanied by ataxia might be most desirable, and these can be approximately read off from an isobol plotted from the results. It was concluded that the marked stimulant effects of the amphetamine-barbiturate mixtures on activity of rats could be regarded as due to true potentiation.

Amobarbital↗
PubMed1962

Actions of a mixture of amphetamine and a barbiturate in man.

The effects in man of a mixture of amphetamine and a barbiturate (15 mg of amphetamine sulphate and 300 mg of cyclobarbitone) and of each of the constituents separately were assessed on the performance of simple mental and motor tasks, on the pulse rate and on subjective reports. The mixture produced a pattern of effects which was different from that produced by either drug separately. It impaired the efficiency of the performance of tasks much less than did the barbiturate drug alone; it produced almost as big a rise in the pulse rate as did amphetamine alone; and it produced reports of feeling "elated" from many more subjects than did either drug separately, though there was no corresponding increase in reports of other feelings and sensations.

Amphetamine↗
PubMed1957

The effect of methylpentynol in man.

Administration of methylpentynol to human subjects depressed their autonomic reactions to a difficult motor task and impaired their performance. Hexobarbitone affected neither autonomic reactions nor performance, though it impaired hand steadiness. The results suggest that the modes of action of methylpentynol and of hexobarbitone are different.

Autonomic Nervous System↗