Effects of systemic injection of interleukin-1 beta on gastric vagal afferent activity in rats lacking type A cholecystokinin receptors

We have shown that systemic administration of interleukin-1 beta (IL-1 beta ) excites gastric vagal afferent activity in part via stimulation of type A cholecystokinin (CCK-A) receptors in rats. The present study was undertake n to determine whether the response of the gastric vagal afferent nerve to systemic IL-1 beta is altered in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, which lack CCK-A receptors. The response was compared with that of th e control strain, Long-Evans Tokushima Otsuka (LETO) rats. All animals were anesthetized with pentobarbital and artificially ventilated. Intravenous a dministration of 4 mu g/kg of IL-1 beta increased gastric vagal afferent ac tivity in both LETO and OLETF rats, whereas a smaller dose of 2 mu g/kg of IL-1 beta increased activity only in the OLETF rats. The present results de monstrate that the response of the gastric vagal afferent activity in CCK-A receptor deficient OLETF rats was more sensitive to intravenous administra tion of IL-1 beta than was in control LETO rats. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.