The colliculus superior modulates ACTH-induced excessive grooming.
In previous studies the involvement of nigrostriatal dopaminergic activity in ACTH(1-24)-induced grooming has been established. It was suggested that the dopaminergic modulation of ACTH(1-24)-induced excessive grooming is exerted through the striato-nigro-collicular pathway. To obtain further evidence it was investigated, whether local application of GABAergic agents into the colliculus superior modulates excessive grooming occurring after an intraventricular injection with ACTH(1-24). It appeared that intra-collicular picrotoxin (a GABAergic antagonist) suppressed ACTH-induced grooming, whereas muscimol (a GABAergic agonist) enhanced the grooming response. The picrotoxin-induced R(unning) F(it) B(ehavior), elicited from the colliculus superior was also seen after intraventricular administration of picrotoxin. A detailed comparison of this behavioral response seen after both routes of administration of picrotoxin suggests that intraventricularly injected picrotoxin may well induce the RFB via a direct effect on the colliculus superior. Lesions placed in the colliculus superior completely abolished picrotoxin-induced RFB, exploration and orientation behavior. Yet, these lesions did not reduce excessive grooming suggesting that although this region may be involved in the modulation of ACTH-induced grooming it is not the primary site of peptide action.
D000324:Adrenocorticotropic Hormone / Q000031:analogs & derivatives*; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003366:Cosyntropin / Q000008:administration & dosage / Q000494:pharmacology*; D018756:GABA Antagonists; D006120:Grooming / Q000187:drug effects / Q000502:physiology*; D007276:Injections, Intraventricular; D008297:Male; D009118:Muscimol / Q000008:administration & dosage / Q000494:pharmacology; D010852:Picrotoxin / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013477:Superior Colliculi / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000502:physiology
D000324:Adrenocorticotropic Hormone; D003366:Cosyntropin; D018756:GABA Antagonists; D009118:Muscimol; D010852:Picrotoxin; D005680:gamma-Aminobutyric Acid