GABAergic and glycinergic mechanisms within the substantia nigra: pharmacological specificity of dopamine-independent contralateral turning behavior and interactions with other neurotransmitters.

Article date: 1979/4/25

PubMed ID: 895876

Journal name: Psychopharmacology (ISSN: 0033-3158)


The pharmacological specificity of the GABA agonist muscimol-induced contralateral turning behavior after unilateral injection into substantia nigra pars reticulata (SNR) has been studied. Muscimol-induced turning was antagonized by intranigral bicuculline methochloride (BMC) and picrotoxin, whereas antagonists of glycine, morphine, dopamine, noradrenaline, and serotonin were ineffective. Glycine induced a qualitatively similar turning behavior which was strychnine-sensitive but relatively BMC and picrotoxin-insensitive. Other drugs, including substance P, kainic acid, clonidine, oxymetazoline, serotonin, and carbachol, induced turning that could be dissociated from the effect of muscimol. Muscimol-induced turning was dopamine-independent, indicated by resistance to haloperidol (1 mg/kg), to pretreatment with reserpine (7.5 mg/kg) plus alpha-methyl-p-tyrosine (200 mg/kg), to haloperidol injections into the SNR, striatum and nucleus accumbens, and finally to kainic acid lesions of the striatum. 6-Hydroxydopamine lesions increased the efficacy of intranigral muscimol, while kainic acid lesions of the SNR antagonized muscimol. Muscimol-induced turning was inhibited by oxotremorine (0.25 mg/kg), by intranigral carbachol, and by apomorphine (0.1–0.5 mg/kg), but only moderately by intranigrally injected apomorphine. These data suggest specificity of GABA-agonist-induced contralateral turning and indicate an interaction between nigral GABA and other neurotransmitters, particularly dopamine and acetylcholine.

Author List: Arnt J, Scheel-Krüger J

Publication Types: Journal Article

Substances mentioned in the article: Hydroxydopamines; Neurotransmitter Agents; Muscimol; gamma-Aminobutyric Acid; Kainic Acid; Glycine; Dopamine;

Mesh terms: Animals; Behavior/drug effects; Dopamine/metabolism; Glycine/physiology; Humans; Hydroxydopamines/pharmacology; Kainic Acid/pharmacology; Male; Muscimol/pharmacology; Neurotransmitter Agents/physiology; Rats; Stereotyped Behavior/drug effects; Substantia Nigra/anatomy & histology; Time Factors; gamma-Aminobutyric Acid/physiology;

Citations: - 1248538

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