Galanin: Ca2+-dependent contractile effects on the isolated mouse distal colon.

Galanin provoked concentration-dependent contractions of the longitudinal muscle of the mouse distal colon. The responses were not affected by atropine, mepyramine, methysergide, phentolamine, timolol, naloxone or tetrodotoxin. In contrast, the contractile responses were reduced by nifedipine and in Ca2+-free medium. These observations indicate that the contractile effects of galanin on the mouse distal colon result from a direct activation of smooth muscle cells and that these effects are mainly dependent on an increase in Ca2+ inflow.