Comparative analysis of the behaviors evoked by bromocriptine and quinpirole (LY 171555) in adult cats.
The aim of this work was to compare the behavioral effects of bromocriptine and quinpirole, two agonists of the D-2 dopaminergic receptor, either injected alone or combined with the D-1 dopaminergic receptor, SKF 38393. In ten adult mongrel cats the following experimental series were carried out: i) a dose-response study with bromocriptine administering 0.5-1.0-4.0 and 8.0 mg/kg s.c.; ii) a behavioral study injecting 4.0 mg/kg of bromocriptine plus 2.0 mg/kg of SKF 38393; iii) the same analysis administering 0.5 mg/kg of LY 171555 plus 1.0 mg/kg of SKF 38393, compared with the same dose of LY 171555 plus 4.0 mg/kg of SKF 38393; iv) an analysis of the behavioral effects of 8.0 mg/kg of bromocriptine compared with 1.0 mg/kg of quinpirole. The main findings were: i) bromocriptine injected, in four different doses evoked decrease in locomotion, and increase in indifference, inappetence, pupillary dilation and limb flicks; ii) the combined administration of 4.0 mg/kg of bromocriptine plus 2.0 mg/kg of SKF 38393 did not elicit behavioral changes different to those produced by bromocriptine alone; iii) quinpirole (1.0 mg/kg) evoked more intense behaviors than bromocriptine (8.0 mg/kg); iv) comparing quinpirole injected alone with the combination of quinpirole plus SKF 38393, this latter treatment produced more intense behaviors than the former. It is concluded: i) SKF 38393 potentiates the behavioral effects produced by quinpirole; this potentiation was not found when bromocriptine was combined with SKF 38393 and ii) the more intense behavioral effect elicited by quinpirole compared with bromocriptine may be explained by the fact that the latter drug is a selective D-2 agonist, whereas the former one is an agonist of the D-2 and the D-3 receptors.
Motles
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E
Departamento de Ciencias Preclínicas Oriente, Facultad de Medicina, Universidad de Chile, Santiago.
Tetas
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M
Gonzalez
M
M
Gomez
A
A
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001971:Bromocriptine / Q000494:pharmacology*; D002415:Cats; D015259:Dopamine Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004873:Ergolines / Q000494:pharmacology*; D005260:Female; D008297:Male; D019257:Quinpirole; D017448:Receptors, Dopamine D2 / Q000187:drug effects
D015259:Dopamine Agents; D004873:Ergolines; D017448:Receptors, Dopamine D2; D019257:Quinpirole; D001971:Bromocriptine; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine