The purpose of this study was to investigate the ultrastructure of the local nerve supply of ovine gallbladders as well as the functional characteristics of inhibitory nerves. We used electron microscopy of thin sections of ovine gallbladders and in vitro isometric tension recording using gallbladder strips. Specifically, we measured contractile and inhibitory responses induced by transmural electrical field stimulation (EFS). We found a ganglionated plexus with intramural nerve cells and interconnecting axons. Clear and large dense-core vesicles colocalized in axons close to smooth muscle cells. EFS elicited gallbladder contractions which were converted to relaxation after atropine. EFS-induced relaxation was reduced by the nitric oxide (NO) synthase inhibitor, L-NOARG and blocked by propranolol and/or tetrodotoxin. In conclusion, enteric ganglia and neurones with synaptic vesicles (clear and dense core) were detected close to smooth muscle bundles. Neural inhibition of gallbladder contraction was mediated by beta-adrenoceptors coupled to NO generation.

Adrenergic Fibers↗

PubMedDate not supplied

Forskolin inhibits platelet deposition in small diameter polytetrafluoroethylene grafts.

Synthetic vascular grafts have a thrombogenic surface which probably is an important factor in graft failure. Systemic pharmacologic intervention has been used but is associated with side effects. In this communication we describe the results of a new therapeutic principle of applying forskolin, a powerful cyclic adenosine monophosphate stimulator (cAMP), to the inner surface of a synthetic graft material, polytetrafluoroethylene. Evaluation was done with Indium-111-oxine labelled platelets and histopathology. It was found that forskolin significantly lowers the platelet deposition onto the treated graft surface compared to controls.

Animals↗