SIMILAR ATYPICAL BETA-ADRENERGIC RECEPTORS MEDIATE IN-VITRO RAT ADIPOCYTE LIPOLYSIS AND COLONIC MOTILITY INHIBITION

We investigated the putative common nature of the rat atypica beta-adr enoceptors mediating white adipocyte lipolysis and proximal colon moti lity inhibition, using the non-selective antagonist alprenolol and ago nist isoprenaline and the selective agonists SR 58611A and BRL 37344. Results in either isolated intestinal and fat tissues were consistent with: isoprenaline acting through both typical (beta1, beta2) and atyp ical beta-adrenoceptors; SR 58611A and BRL 37344 acting solely through the latter. The identical pA2 values obtained with alprenolol, irresp ective of the tissue and the selective agonist (SR 58611A or BRL 37344 ) used, support the high functional homology of the atypical beta-adre noceptors in rat colon and adipocytes.