par Delporte, Christine ;Poloczek, Piotr ;De Neef, Philippe ;Vertongen, Pascale ;Ciccarelli, Ernesto ;Svoboda, Michal ;Herchuelz, André ;Winand, Jacques ;Robberecht, Patrick
Référence Molecular and cellular endocrinology, 107, 1, page (71-76)
Publication Publié, 1995-01
Référence Molecular and cellular endocrinology, 107, 1, page (71-76)
Publication Publié, 1995-01
Article révisé par les pairs
Résumé : | The properties of the pituitary adenylate cyclase activating polypeptide (PACAP) type I receptor were studied on a clone of Chinese hamster ovary cells (CHO) stably transfected with the recombinant receptor. PACAP(1-27), PACAP(1-38) and VIP inhibited [125I-acetyl-His1]PACAP (1-27) binding, stimulated cyclic AMP and inositol phosphates production and induced [Ca2+]i increase with the same order of potency: PACAP(1-27) = PACAP(1-38) > VIP. The concentrations required for half maximal receptor occupancy, IP3- and [Ca2+]i increase were not different for both PACAPs (1 nM) and 100-fold higher than those required for cyclic AMP increase (0.010 nM).These data suggest that the occupancy of a portion of the total receptors available was sufficient for maximal cyclic AMP production but not for maximal IP3 production. It is concluded that the possibility of the type I PACAP receptor being coupled to a transduction pathway is not located at the level of the ligand but rather at the level of the G-proteins. © 1995. |