Background
Previous studies have demonstrated that centrally administered natriuretic peptides and pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) have hyperthermic properties. Isatin (indole-2, 3-dione) is an endogenous indole that has previously been found to inhibit hyperthermic effects of natriuretic peptides. In this study the
Conclusion
The mechanisms that participate in the mediation of the PACAP-38-induced hyperthermia may be modified by isatin. The capability of isatin to antagonize the hyperthermia induced by all members of the natriuretic peptide family and by PACAP-38 makes it unlikely to be acting directly on receptors for natriuretic peptides or on those for PACAP in these hyperthermic processes.
Results
One microg intracerebroventricular (icv.) injection of PACAP-38 had hyperthermic effect in male, Wistar rats, with an onset of the effect at 2 h and a decline by the 6th h after administration. Intraperitoneal (ip.) injection of different doses of isatin (25-50 mg/kg) significantly decreased the hyperthermic effect of 1 microg PACAP-38 (icv.), whereas 12.5 mg/kg isatin (ip.) had no inhibiting effect. Isatin alone did not modify the body temperature of the animals.