Search results for "Vasoactive intestinal peptide"
showing 3 items of 43 documents
VIPoma and PPoma
2015
Gastrinomas are rare tumors of the neuroendocrine system, occurring within the pancreas and duodenum. The annual incidence is estimated at 0.5 per million of the population [1]. Overproduction of gastrin by these tumors produces a sustained increase in gastric acid secretion, leading to clinical manifestations of complicated peptic ulcer disease known as the Zollinger-Ellison syndrome (ZES) [2]. Although most gastrinomas grow slowly, over 60 % are malignant and 25 % show rapid aggressive behavior [3-5]. Most commonly gastrinomas metastasize to regional lymph nodes and the liver, and it is this malignant potential which has become increasingly important since the introduction of effective me…
Vasoactive intestinal peptide stimulation of cyclic guanosine monophosphate formation: further evidence for a role of nitric oxide synthase and cytos…
1993
In the rat pineal gland vasoactive intestinal peptide (VIP) and beta-adrenergic agonists stimulate cyclic guanosine monophosphate (cGMP) formation and their action is amplified by alpha 1-adrenergic agonists. Since beta-adrenergic stimulation of cGMP is suggested to involve activation of nitric oxide (NO) synthase and NO-mediated activation of cytosolic guanylate cyclase (GC), we investigated the effects of the NO synthase inhibitor N-monomethyl-L-arginine (L-NMMA) and of the cytosolic GC inhibitor methylene blue (MB) on VIP receptor-stimulated cGMP formation. Both L-NMMA and MB depressed VIP-induced cGMP formation as well as alpha 1-adrenergic potentiation of VIP-stimulated cGMP formation …
Enkephalin-containing interneurons are specialized to innervate other interneurons in the hippocampal CA1 region of the rat and guinea-pig
1998
Enkephalins are known to have a profound effect on hippocampal inhibition, but the possible endogenous source of these neuropeptides, and their relationship to inhibitory interneurons is still to be identified. In the present study we analysed the morphological characteristics of met-enkephalin-immunoreactive cells in the CA1 region of the rat and guinea-pig hippocampus, their coexistence with other neuronal markers and their target selectivity at the light and electron microscopic levels. Several interneurons in all subfields of the hippocampus were found to be immunoreactive for met-enkephalin. In the guinea-pig, fibres arising from immunoreactive interneurons were seen to form a plexus …