BACKWARD WALKING AND CIRCLING: BEHAVIOURAL RESPONSES INDUCED BY DRUG TREATMENTS WHICH CAUSE SIMULTANEOUS RELEASE OF CATECHOLAMINES AND 5‐HYDROXYTRYPTAMINE
British Journal of Pharmacology – August 01, 1979
Source: OpenAlex
Summary
Simultaneous release of Dopamine and Serotonin drives unusual motor behaviors like backward walking and circling in rats. Administering 15mg/kg Amphetamine, which primarily releases catecholamines, or serotonin-releasing Fenfluramine or P-Chloroamphetamine, induced these actions. Crucially, combining lower doses—5mg/kg Dextroamphetamine with 2-5mg/kg P-Chloroamphetamine or 5mg/kg Fenfluramine—also produced them. Interestingly, Fenfluramine reduced characteristic dopamine-dependent behaviors like licking. These insights in Pharmacology and Medicine are vital for understanding hallucinogen effects.
Abstract
The roles of catecholamine and 5‐hydroxytryptamine (5‐HT) release in mediating backward walking and circling were studied in rats. These behaviours occurred in animals given 15mg/kg intraperitoneally of (+)‐amphetamine (which predominantly releases catecholamines) or either p ‐chloroamphetamine or fenfluramine (which predominantly release 5‐HT). They also occurred when smaller doses of (+)‐amphetamine (5mg/kg) and either p ‐chloroamphetamine (2–5 mg/kg) or fenfluramine (5 mg/kg) were given together. Characteristic dopamine‐dependent behaviours (rearing, licking, gnawing) resulting from (+)‐amphetamine injection were greatly reduced by p ‐chloroamphetamine or fenfluramine. Characteristic 5‐HT‐dependent behaviours (wet dog shake, hind limb abduction) resulting from injection of either p ‐chloroamphetamine or fenfluramine were unaffected by (+)‐amphetamine. Fragmentary backward walking and circling resulting from levallorphan injection (50 mg/kg s.c.) were decreased by (+)‐amphetamine at low dosage. Results in general strengthen previous evidence that backward walking and circling are mediated by simultaneous dopamine and 5‐HT release. The possible relevance of the above findings to hallucinogenic activity, amphetamine psychosis, schizophrenia and abnormal movements due to l ‐DOPA treatment is discussed.