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EFFECTS OF DRUGS ACTING ON CEREBRAL 5‐HYDROXYTRYPTAMINE MECHANISMS ON DOPAMINE‐DEPENDENT TURNING BEHAVIOUR IN MICE
Author(s) -
MILSON J.A.,
PYCOCK C.J.
Publication year - 1976
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1976.tb06961.x
Subject(s) - dopamine , neuroscience , pharmacology , medicine , psychology
1 The effects of drugs acting on cerebral 5‐hydroxytryptaminergic mechanisms on drug‐induced turning behaviour in mice with unilateral destruction of nigro‐striatal dopaminergic nerve terminals have been studied. 2 Administration of l ‐tryptophan (400 mg/kg) or 5‐hydroxytryptophan (200 mg/kg) increased brain 5‐hydroxytryptamine and decreased the turning induced by both apomorphine (2 mg/kg) and amphetamine (5 mg/kg). 3 Parachlorophenylalanine (3 × 500 mg/kg) decreased brain 5‐hydroxytryptamine and increased both apomorphine and amphetamine‐induced circling behaviour. 4 Varying the protein content of dietary intake significantly altered brain 5‐hydroxytryptamine and tryptophan levels, spontaneous locomotor activity and amphetamine‐induced circling behaviour in these mice. 5 Systemic administration of methysergide (0.5–4 mg/kg), lysergic acid diethylamide (0.025‐0.2 mg/kg), cyproheptadine (2.5–20 mg/kg) or clomipramine (0.6–20 mg/kg) produced no consistent effect on drug‐induced turning behaviour. 6 The results suggest that circling behaviour due to striatal dopamine receptor stimulation is depressed by an elevation of brain 5‐hydroxytryptamine and enhanced by a reduction in brain 5‐hydroxytryptamine. 7 The possible physiological relationship between dopamine and 5‐hydroxytryptamine neurones in the basal ganglia is discussed.