Vagal Relaxation of the Stomach Induced from the Gastric Antrum

A brahamsson , H. Vagal relaxation of the stomach induced from the gastric antrum. Acta physiol scand. 1973. 89. 406–414. The effect of mechanical stimulation of the gastric antrum on gastric (corpus‐fundus) motility was studied in anesthetized cats. Antral distension elicited a pronounced corpus‐fundus relaxation which was not blocked by atropine, guanethidine or by cervical spinal cord transection but was abolished by blockade of the vagal nerves. The “threshold stimulus” for eliciting the reflex response was an antral distension pressure between 5 and 10 cm H 2 O. Stepwise increases of antral distension produced correspondingly increased corpus‐fundus relaxations. A steady antral distension could keep the corpus‐fundus part relaxed for at least 10 min. La. infusion of acetylcholine to the antrum produced antral contractions followed by a marked corpus‐fundus relaxation which persisted after guanetnidine. Electric afferent stimulation of antral nerve branches elicited a gastric relaxation similar to the corpus‐fundus response to antral distension.‐It is concluded that activation of slowly adapting “tension receptors”, located in the antral gastric wall and with vagal afferents, elicits gastric relaxation by a reflex activation of the vagal non‐adrenergic rclaxatory fibres to the stomach. These reflex mechanisms are suggested to be involved in the control of gastric reservoir function (receptive relaxation) and gastric emptying. Some effects of vagotomy on gastric motility are discussed in relation to the present findings.