An alpha 2-adrenergic mode of action of chlordimeform on rat visual function.
The hypothesis that chlordimeform increased the amplitude of components N1P1 and P1N3 in rat pattern-reversal visual evoked potentials through actions on alpha 2-adrenergic receptors was tested with two sets of experiments. First, rats received single injections of either vehicle, an alpha 2-adrenergic antagonist yohimbine (0.1, 0.5, or 2.0 mg/kg), or an alpha 2-adrenergic agonist clonidine (0.05, 0.1, or 0.5 mg/kg). Yohimbine alone had no effect on pattern-reversal evoked potential amplitude. Clonidine treatment produced a dosage related increase in amplitude of both components similar to that produced by chlordimeform (W.K. Boyes and R.S. Dyer, 1984, Brain Res. Bull., 10, 817-823). Second, rats were given double injections of either vehicle or yohimbine (0.05, 0.5, 2.0, or 5.0 mg/kg) followed by either vehicle, clonidine (0.1 or 0.2 mg/kg) or chlordimeform (10, 20, or 40 mg/kg). Yohimbine pretreatment attenuated the effects of subsequent treatment with either clonidine or chlordimeform. These results support the hypothesis that chlordimeform alters rat pattern-reversal evoked potentials through actions as a central nervous system alpha 2-adrenergic agonist.
Boyes
W K
WK
Neurotoxicology Division, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27711.
Moser
V C
VC
D000578:Amidines / Q000633:toxicity*; D000818:Animals; D001831:Body Temperature / Q000187:drug effects; D002742:Chlorphenamidine / Q000633:toxicity*; D003000:Clonidine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005074:Evoked Potentials, Visual / Q000187:drug effects*; D007306:Insecticides / Q000633:toxicity*; D008297:Male; D051381:Rats; D011930:Reaction Time / Q000187:drug effects; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D015016:Yohimbine / Q000494:pharmacology
D000578:Amidines; D007306:Insecticides; D011942:Receptors, Adrenergic, alpha; D015016:Yohimbine; D002742:Chlorphenamidine; D003000:Clonidine