Influence of thiorphan and phosphoramidon on the relaxant effect of vasoactive intestinal polypeptide and non-adrenergac non-cholinergic neurone stimulation in the rat gastric fundus

Relaxations were induced in longitudinal muscle strips of the rat gastric fundus by exogenous administration of vasoactive intestinal polypeptide (VIP) and by transmural stimulation in the presence of atropine. These responses were not influenced by two neutral endopeptidase inhibitors, thiorphan (3 × 10⁻⁵ M) and phosphoramidon (10⁻⁵ M). This suggests that neutral endopeptidase is not involved in the breakdown of exogenous VIP and non-adrenergic non-cholinergic inhibitory transmitters of the rat gastric fundus.