Sensitization of dural afferent nerve endings modulates high voltage active calcium currents of primary sensory neurons / 中华神经医学杂志

ABSTRACT

Objective To investigate the modulation of sensitization of dural afferent nerve endings on high voltage active calcium currents (HVA-ICa) of primary sensory neurons from rat trigeminal ganglion. Methods Male adult SD rats were randomly divided into normal saline treatment group (NS,n=8) and proinflammatory agent plus calcitontin gene-related peptide infusion group (IS+CGRP,n=8).One h after the infusion,the effect of CGRP on currents of voltage-gated calcium channel (VGCC) in neurons acutely isolated from trigeminal ganglion was recorded using a conventional whole-cell recording patch clamp technique. Results The peak level of calcium current in the IS+CGRP group ( [-80.48±4.43] pA/pF) was significantly increased as compared with that in the NS group ([-49.5±5.18] pA/pF); the half-activation voltage (Va1/2) in the activation curve of calcium current in the IS+CGRP group ([-20.9±0.4] mV) moved 4.7 mV to the hyperpolarization direction as compared with that in the NS group ([-16.2±0.5] mV) with significant difference (P＜0.05); the half-inactivation voltage (Vi1/2) in the activation curve of calcium current in the IS+CGRP group ([-12.4±0.2] mV) moved 10.1 mV to the depolarization direction as compared with that in the NS group ([-22.5 ±0.3] mV) with significant difference (P＜0.05). Conclusion Sensitization of dural afferent nerve endings facilitates peripheral sensitization of primary sensory neurons, with an outstanding performance as increment of calcium current.