title: SKF 38393 potentiates yawning induced by LY 171555: further evidence against the autoreceptor hypothesis of yawning.
abstract: The effect of concurrent D-1 receptor stimulation by SKF 38393 on the expression of yawning elicited by D-2 receptor stimulation with LY 171555 was studied in the rat. A low dose of SKF 38393 (2.5 mg/kg SC), while failed to elicit yawning, potentiated the effectiveness of LY 171555 in eliciting yawning at all the doses tested (12.5, 25 and 50 micrograms/kg SC) and this effect was abolished by SCH 23390 (0.012 mg/kg SC). The results indicate that in analogy with typical post-synaptic dopaminergic effects (hypermotility-stereotypy), yawning elicited by a D-2 agonist is facilitated by concurrent stimulation of D-1 receptors and therefore is consistent with previous evidence that yawning in response to a D-2 agonist is not mediated by autoreceptors.
authors.affiliation: Institute of Experimental Pharmacology and Toxicology, University of Cagliari, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Spina
authors.forename: R
authors.initials: R
authors.lastname: Longoni
authors.forename: A
authors.initials: A
authors.lastname: Mulas
authors.forename: G
authors.initials: G
authors.lastname: Di Chiara
mesh_terms: D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D015259:Dopamine Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004873:Ergolines / Q000494:pharmacology*; D008297:Male; D019257:Quinpirole; D051381:Rats; D011919:Rats, Inbred Strains; D011954:Receptors, Dopamine / Q000187:drug effects*; D015000:Yawning / Q000187:drug effects*
chemical_list: D001552:Benzazepines; D015259:Dopamine Agents; D004873:Ergolines; D011954:Receptors, Dopamine; D019257:Quinpirole; D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine