1. Differential nociceptive responses in mice lacking the α1B subunit of N-type Ca2+ channels
- Author
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Shin'ich Shoji, Keiji Imoto, Norimasa Miyamoto, Shinji Hatakeyama, Kohei Sawada, Yasuo Mori, Takashi Yoshinaga, Mitsuhiro Ino, Tetsuhiro Niidome, Toshihiro Yoshizawa, Minoru Wakamori, Yukio Nishizawa, Isao Tanaka, and Eiki Takahashi
- Subjects
Male ,Pain Threshold ,medicine.medical_specialty ,Hot Temperature ,Patch-Clamp Techniques ,Central nervous system ,Alpha (ethology) ,Synaptic Transmission ,Membrane Potentials ,Mice ,Calcium Channels, N-Type ,omega-Agatoxin IVA ,Dorsal root ganglion ,omega-Conotoxin GVIA ,Ganglia, Spinal ,Physical Stimulation ,Internal medicine ,medicine ,Animals ,Hot plate test ,Muridae ,Mice, Knockout ,Synaptosome ,biology ,Chemistry ,General Neuroscience ,Nociceptors ,Calcium Channel Blockers ,Spinal cord ,biology.organism_classification ,Posterior Horn Cells ,medicine.anatomical_structure ,Nociception ,Endocrinology ,Nimodipine ,Neuroscience - Abstract
The role of N-type Ca(2+) channels in nociceptive transmission was examined in genetically engineered mice lacking the alpha(1B) subunit of N-type channels and in their heterozygote and wild-type littermates. In alpha(1B)-deficient mice, N-type channel activities in dorsal root ganglion neurons and spinal synaptoneurosomes were eliminated without compensation by other types of voltage-dependent Ca(2+) channels. The alpha(1B)-deficient mice showed a diminution in the phase 2 nociceptive responses more extensively than in the phase 1 nociceptive responses of the formalin test. The alpha(1B)-deficient mice exhibited significantly increased thermal nociceptive thresholds in the hot plate test, but failed to increase mechanical nociceptive thresholds in the tail pinch test. These results suggest a crucial role of N-type channels in nociceptive transmission, especially for persistent pain like phase 2 of the formalin test and for nociception induced by thermal stimuli.
- Published
- 2001
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