Canine jejunal submucosa cultures: characterization and release of neural somatostatin.

A primary culture of the canine jejunal submucosa has been established and used to investigate neuronal somatostatin release. Immunocytochemical characterization of the cultures demonstrated the presence of the following peptidergic neurons: neurotensin (30%), somatostatin (27%), vasoactive intestinal polypeptide (14%), neuropeptide Y (10%), and substance P (5%). No immunoreactive neurons were observed with the available antisera to galanin, gastrin-releasing peptide, and motilin. The concentration of somatostatin-like immunoreactivity, as determined by radioimmunoassay of cell extracts, was 358 +/- 105 pmol/well. Basal release of somatostatin was 4.4 +/- 0.9% total cell content and was significantly inhibited by the addition of substance P at 1 and 100 nM. The addition of the calcium ionophore, A23187, with phorbol 12-myristate 13-acetate stimulated somatostatin release in a concentration-dependent manner. These data indicate that short-term cultures of the jejunal submucosal plexus will be an excellent model for determination of the factors influencing the release of neural somatostatin.