Effect of pertussis toxin on baclofen- and diphenhydramine-induced amnesia

Abstract

The effect of pretreatment with pertussis toxin at the doses of 0.25 and 0.50 μg per mouse ICV on the amnesic effect produced by baclofen (0.1–4 mg kg⁻¹ IP), diphenhydramine (15–30 mg kg⁻¹ IP) and scopolamine (0.5–5 mg kg⁻¹ IP) was investigated in the mouse passive avoidance test. Ten days after a single injection of pertussis toxin, baclofen (2–4 mg kg⁻¹ IP) amnesia was prevented. By contrast, pertussis toxin had no effect on diphenhydramine- and scopolamine-induced amnesia. Pretreatment with pertussis toxin at both doses used did not impair motor coordination of the mice, as revealed by the rota-rod test. The present results indicate that the activation of pertussis toxin-sensitive G-proteins represents an important transduction step in memory impairment induced by GABA_B (γ-aminobutyric acid B) agonists, but not by antihistaminic and antimuscarinic drugs.