| Abstract: | In acute experiments on chloralosed cats gastric motility, blood pressure and heart rate were investigated for influences exerted by the fastigial nucleus. Besides pressor responses, fastigial stimulation could produce either gastric excitation or relaxation and the background of these responses was analysed by selective nerve sectioning and administration of suitable autonomic blocking agents. Suppression of prevailing gastric motility was found to be mediated mainly by increased discharge in adrenergic nerve fibres but also by adrenal catecholamine release. -- Gastric excitation could be induced in three different ways, first via increased activity in vagal cholinergic fibres, second, by fastigial suppression of the vago-vagal non-adrenergic relaxatory reflex. In addition, when laparotomy or other noxious abdominal stimuli had induced inhibitory gastric reflexes, the consequent sympathetic discharge could be suppressed by fastigial stimulation resulting in enhanced gastric motility. -- The importance of background activity in the various nervous pathways for the fastigially induced gastric responses is discussed. |
