Pressure and length adaptations in isolated cat stomach.

Correlations were made between the adaptation of gastric pressure and longitudinal muscle tension. Isolated cat stomachs were filled with physiological solution and longitudinal strips marked in five segments over the lesser and the greater curvature (LC and GC). Strip length changed the most in the proximal segments of GC. Volume changes led to triphasic changes in gastric pressure. On filling, there was a pressure peak and pressure accommodation to a new base-line pressure. On emptying there was an initial pressure nadir that was followed by a pressure recovery. When isolated longitudinal strips were stretched and released to their lengths at specific gastric volumes, they generated triphasic tension adaption and recovery. Strips from the proximal greater curvature generated the highest base-line tension, highest peak tension, and largest amplitude of tension adaptations. Addition of KCl, carbachol, or physostigmine increased base-line tension and tension adaptations in parallel, whereas atropine reduced them. Tetrodotoxin had no effect. The base-line tension of the isolated cat stomach is maintained by a tonic cholinergic neurosecretion but its tension adaptations do not require neural control.