R-type(Cav2.3) calcium channel contributes to pain sensation in peripheral sensory neurons. Six isoforms of Cav2.3 that result from combinations of presence or deletion of three inserts(insert I and insert in the II-III loop, and insert III in N-terminal regions) have been demonstrated to be present in different mammalian tissues. However, the molecular basis of Cav2.3 in trigeminal ganglion(TG) neurons is not known. In the present study, we determined which isoforms of Cav2.3 are expressed in rat TG neurons using the RT-PCR analysis. Whole tissue RT-PCR analyses revealed that only two isoforms, Cav2.3a and Cav2.3e, were present in TG neurons. From single-cell RT-PCR, we found that Cav2.3e rather than Cav2.3a was the major isoform expressed in TG neurons, and Cav2.3e was preferentially detected in small-sized neurons that express nociceptive marker, transient receptor potential vanilloid 1(TRPV1). Our results suggest that Cav2.3e in trigeminal neurons may be a potential target for the pain treatment.

• Seog Bae Oh(Department of Physiology and Program in Molecular and Cellular Neuroscience, College of Dentistry and Dental Research Institute, Seoul National University) Corresponding author
• Joong Soo Kim(Department of Physiology and Program in Molecular and Cellular Neuroscience, College of Dentistry and Dental Research Institute, Seoul National University)
• Zhi Fang(Department of Physiology and Program in Molecular and Cellular Neuroscience, College of Dentistry and Dental Research Institute, Seoul National University)