Gastric acid secretion caused by gastrin-17 injection into both sides of the hypothalamic paraventricular nucleus in rats.

Gastric acid outputs were examined after gastrin-17 (gastrin) injection into either side of the hypothalamic paraventricular nucleus (PVN) or both sides of the PVN in bilaterally adrenalectomized rats. The acid output increased when 40 pM gastrin was unilaterally injected (10 s, 500 nl) into the PVN through a 28-gauge stainless steel tube. The acid output was also increased when 80 pM gastrin was iontophoretically injected (2 min, -50 nA) into the PVN through a glass tube. An additive increase in the acid output was elicited when an effective concentration of gastrin was simultaneously injected into both sides of the PVN. It was also noted that there was a significant increase in acid output when an ineffective concentration of gastrin was simultaneously injected into both sides of the PVN. Almost the same magnitude of acid response due to PVN gastrin was reproduced in normoglycemia, but it was diminished in hyperglycemia. These results suggest that PVN neurons sensitive to gastrin form a neural circuit in both sides of the nucleus, and the circuit acts to potentiate the stimulation of gastric acid which is dependent on the glycemic condition.