Effects of modifications of gastric motility on the membrane potential of the coeliac ganglionic neurons in the rabbit

The involvement of gastric motility in the slow variations of membrane potential of sympathetic ganglionic neurons was investigated in rabbit. The present study was performed in vitro on the coeliac plexus connected to the stomach. The electrical activity of ganglionic neurons was investigated using intracellular recording techniques. Spontaneous increases in basal intragastric pressure triggered slow hyperpolarizations of the ganglionic neurons (n = 7), the duration of which was similar to that of the increase in the basal pressure. Conversely, cooling of the nerve trunks connecting the coeliac plexus to the stomach induced a slow depolarization of the ganglionic neurons (n = 3). Carbachol-induced increases in basal intra-gastric pressure modified the membrane potential of ganglionic neurons in several ways: hyperpolarization (n = 6), depolarization (n = 4), hyperpolarization followed by depolarization (n = 2), and these modifications lasted longer than the modifications of gastric motility. After cooling of the nerve trunks connecting the coeliac plexus to the stomach, the carbachol-induced variations of gastric motility were no longer able to modify the membrane potential of the ganglionic neurons. These results demonstrate that modifications of the gastric motility can trigger slow modifications of the resting membrane potential of coeliac neurons and therefore could modify their excitability. This suggests that gastric motility can modify at the postsynaptic level the transmission of central or peripheral inputs to ganglionic neurons.