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Biomedical subjects

P H Redfern

Publications and source records attributed to P H Redfern.

At least 55 records · Page 3Linked to original sources
PubMed1976

Brain acetylcholine concentration and acetylcholinesterase activity in selectively-bred strains of rats.

Significant differences in whole brain and in brain area acetylcholine concentration have been observed between the two strains of rats selectively bred for differences in speed of acquisition of conditioned avoidance. Brain acetylcholinesterase activity was similar in the strains. The strain showing poor conditioned avoidance behaviour possessed the highest brain concentration of acetylcholine. The finding supports a theory which describes a central cholinergic inhibitory system which may be active in the control of certain types of learning behaviour.

Acetylcholine↗
PubMed1976

Studies on the mechanism of action of amantadine.

1 The effect of amantadine hydrochloride on various aspects of catecholamine metabolism in the rat brain has been investigated. 2 Amantadine failed to have any significant effect on brain concentrations of dopamine or noradrenaline even when administered daily for 9 days. 3 Amantadine had no effect on the rate of decline of noradrenaline and dopamine concentrations after alpha-methyl-p-tyrosine. 4 In vitro amantadine inhibited dopamine uptake into synaptosomes only at high concentrations, and caused little release of dopamine from synaptosomes. 5 There is no evidence from these results to suggest that the anti-Parkinsonian effect of amantadine is related to an action on dopaminergic mechanisms.

Amantadine↗
PubMed1974

The effect of phase-shift on the passive avoidance response in rats and the modifying action of chlordiazepoxide.

1 In rats trained to a 12 h light-12 h dark cycle, advancing the phase by 6 h produced a resynchronization of the 24 h variation in passive avoidance response (PAR) which was completed after 10 days.2 The attainment of the new steady state was preceded by a period of disruption which was greatest 5 days after phase-shift.3 The presence of chlordiazepoxide (62.5-500 mug/ml) in the drinking water during the days after phase-shift produced a dose-dependent lessening of the disruptive effect of phase-shift, and a more rapid adaptation to the new light-dark cycle.

Animals↗