Characterization of the effects of scopolamine on the habituation of exploratory activity: differential effects of oxotremorine and physostigmine.
1. Habituation was regarded as a difference between exploratory activity measured first (session 1) and that measured second (session 2) in a novel environment. 2. Scopolamine (1.0 mg/kg) significantly increased the horizontal activity in sessions 1 and 2 when administered prior to session 1, resulting in the impairment of habituation. 3. Haloperidol (0.2 mg/kg) inhibited scopolamine-induced hypermotility in session 1, but it did not inhibit the scopolamine-induced impairment of habituation in session 2. 4. The direct cholinergic agonist oxotremorine (0.03 mg/kg), unlike the cholinesterase inhibitor physostigmine, significantly inhibited the scopolamine-induced impairment of habituation in the horizontal and vertical activities. 5. These results suggest that the direct stimulation of cholinergic receptors is more effective for scopolamine-induced amnesia than the indirect stimulation of cholinergic receptors by cholinesterase inhibitors in the habituation task.
Ukai
M
M
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, Meijo University, Nagoya, Japan.
Kobayashi
T
T
Kameyama
T
T
D000647:Amnesia / Q000139:chemically induced; D000818:Animals; D005106:Exploratory Behavior / Q000187:drug effects*; D006185:Habituation, Psychophysiologic / Q000187:drug effects*; D006220:Haloperidol / Q000494:pharmacology; D007858:Learning / Q000187:drug effects; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000187:drug effects; D010095:Oxotremorine / Q000494:pharmacology*; D010830:Physostigmine / Q000494:pharmacology*; D011976:Receptors, Muscarinic / Q000187:drug effects; D012153:Retention, Psychology / Q000187:drug effects; D012601:Scopolamine / Q000494:pharmacology*
D011976:Receptors, Muscarinic; D010095:Oxotremorine; D010830:Physostigmine; D012601:Scopolamine; D006220:Haloperidol