Tripelennamine enhances buprenorphine-, but not pentazocine-induced hyperactivity in mice

The opioid agonist-antagonist pentazocine (1-30 mg/kg) and the partial agonist buprenorphine (0.05-0.25 mg/kg) were tested, alone or in combination with the histamine H1-receptor antagonist tripelennamine (1, 2.5, 5 or 10 mg/kg), on locomotor activity in mice of the CD-1 strain. When given alone, pentazocine produced slight and non-dose-related activity increments, while buprenorphine induced strong and dose-related locomotor stimulation. Tripelennamine slightly increased activity by itself and enhanced buprenorphine-, but not pentazocine-induced hyperactivity. The results are discussed in relation to the hypothesis that antihistaminic agents specifically interfere with locomotor effects of opioids.