Hypothermic effect of intracerebroventricular injections of taurine on endotoxin-induced fever in rabbits

Taurine (Tau) was infused by intracerebroventricular (icv) injection 20 min after iv endotoxin (ET). Cerebrospinal fluid was taken from the posterior cisterns at 0, 60, 210 and 390 min after Tau infusion. The concentrations of cAMP and PGE2 in the samples were determined by radioimmunoassay. In the control groups, an equivalent isotonic saline (NS) (non-pyrogenic) instead of Tau or ET was used respectively. The rectal and ear skin temperatures of the rabbits in a non-fasting state were recorded automatically. Tau icv 1.0 mg/50 microliters, followed by the slow infusion of Tau 0.06-0.22 mg/(kg.min) for about 20 min into rabbits, caused sedation and peripheral vasodilation (rise in ear skin temperature), and initially blocked the rise in rectal temperature induced by ET (iv, 1 micrograms/kg). The results for the control groups were significantly different from those of the ET + Tau group. In the ET + NS group, the fluctuations in concentrations of PGE2 and cAMP paralleled the change in rectal temperature, but in the ET + Tau group, the changes in PGE2 and cAMP concentrations were similar to those of the ET + NS group, even though the fever was initially inhibited. There were no changes in the concentrations of these mediators in the NS + Tau group.