Exp Neurobiol 2007; 16(1): 27-33

Published online July 1, 2007

© The Korean Society for Brain and Neural Sciences

Characteristics of Cholinergic Receptors in Nigrostriatal Neurons

Kyung Hee Lee1, Insop Shim2, Sun Jun Bai3, Kang Kyung Sung4, Zang-Hee Cho5, Hye-Jung Lee6 and Bae Hwan Lee1*

1Department of Physiology, Yonsei University College of Medicine, Seoul 120-752, 2Department of Integrative Medicine, College of Medicine, The Catholic University of Korea, Seoul 137-701, 3Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, Seoul 120-752, 4Department of Neuroscience and Internal Medicine, College of Oriental Medicine, Wonkwang University, Iksan 570-749, 5Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon 405-760, 6Acupuncture and Meridian Science Research Center, Kyung Hee University, Seoul 130-701, Korea

Correspondence to: *To whom correspondence should be addressed.
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Brain dopaminergic system has various important functions such as attention, locomotion, and sensory-motor integration. Although nicotine has a medical problem like addiction, it can activate brain dopaminergic system. The present study was conducted to determine the characteristics of nigrostriatal dopaminergic neurons by focusing on the relative contribution of nicotinic and muscarinic receptors and on sensitivity to alpha-bungarotoxin in nicotinic receptors. Under urethane anesthesia, the responses of nigrostriatal neurons of the male Sprague-Dawley rats to iontophoretically applied cholinergic chemicals were recorded. Nigrostriatal neurons showed high basal firing frequency. These neurons were more activated following the ejection of nicotine than muscarine. The distribution of receptors sensitive to alpha-bungarotoxin was relatively high compared to receptors insensitive to alpha-bungarotoxin. These results suggest that midbrain SNpc neurons reveal the distinct characteristics in terms of nicotinic receptors.

Keywords: nigrostriatal neurons, nicotine, alpha-bungarotoxin, cholinergic receptors