INHIBITORY EFFECTS OF SHORT INTRAVASCULAR INFUSIONS OF PROPIONATE ON RETICULORUMEN MOTILITY IN THE SHEEP

The effect of short infusions into the hepatic portal vein of propiona te on reticulo-rumen motility was examined in conscious sheep. Infusio ns of 10 min duration of propionate at 1-6 mmol.min(-1) into the porta l vein reduced the frequency and amplitude of reticulum and rumen cont ractions, especially the amplitude of rumen contractions. Inhibitory e ffects were not confined to the portal route and were also obtained vi a the jugular vein, carotid artery, coeliac artery and anterior mesent eric artery. Butyrate was also effective, but acetate much less so and NaCl almost without effect. The inhibitory responses remained after s ection of nerves to the liver. It appears unlikely the effects reflexl y originate from the liver or are derived centrally.