Characterization of acute somatosensory pain transmission in P/Q-type Ca(2+) channel mutant mice, leaner.

To study the role of the Ca(v)2.1/alpha(1A) (P/Q-type) Ca(2+) channel in somatosensory pain processing, behavioral and electrophysiological studies were conducted using the leaner (tg(la)/tg(la)) mouse. Behavioral analyses in tg(la)/tg(la) revealed reduced responses to mechanical stimuli, and enhanced responses to heat stimuli. Electrophysiological analyses showed that tg(la)/tg(la) had a significantly reduced ability to evoke dorsal root potentials, suggesting a functional deficit in the spinal dorsal horn local circuitry responsible for presynaptic inhibition of primary sensory fibers. These results suggest the critical importance of the P/Q-type channel in modulation of acute somatosensory pain transmission in spinal cord.