Motor responses of autoimmune NZB/B1NJ and C57BL/6Nnia mice to arecoline and nicotine.
In 11-13 month C57BL/6Nnia mice, arecoline produced a dose-dependent decrease in motor activity at doses of 0.64-2.5 mg/kg, whereas at doses of 5.0-20.0 mg/kg arecoline produced a dose-dependent increase in motor activity. In marked contrast, age-matched NZB/B1NJ (New Zealand Black) mice failed to exhibit the first phase of the response, but showed a greater dose-dependent increase in motor activity following the doses of 10 and 20 mg/kg. Nicotine, 0.64-2.5 mg/kg, produced a dose-dependent decrease in motor activity in both strains. The effects of arecoline and nicotine were antagonized by scopolamine (2.5 mg/kg) and mecamylamine (1.0 mg/kg), respectively. These findings suggest that muscarinic neurotransmission may be altered in NZB/B1NJ mice, which produce brain-reactive autoantibodies, exhibit learning/memory dysfunctions, and also exhibit a loss of neurons staining positive for choline acetyltransferase.
Department of Pharmacology, Texas College of Osteopathic Medicine, Camp Bowie at Montgomery, Fort Worth 76107-2690.
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D000818:Animals; D001115:Arecoline / Q000009:adverse effects / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL / Q000235:genetics*; D008814:Mice, Inbred NZB / Q000235:genetics*; D009043:Motor Activity / Q000187:drug effects*; D009538:Nicotine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011976:Receptors, Muscarinic / Q000187:drug effects; D012601:Scopolamine / Q000494:pharmacology; D012827:Silicone Oils; D014202:Tremor / Q000139:chemically induced
D011976:Receptors, Muscarinic; D012827:Silicone Oils; D001115:Arecoline; C054077:fluorosilicone oil; D008464:Mecamylamine; D009538:Nicotine; D012601:Scopolamine