Voltage-dependent calcium channel subtypes controlling somatic substance P release in the peripheral nervous system

Abstract 1. 1. Isolated rat dorsal root ganglia (DRG) neurones support vesicular, non synaptic release of substance P in a depolarisation and Ca ++ dependent manner. 2. 2. In vivo this process may mediate cross-communication between DRG cells in some neuropathological conditions and is therefore a putative area for drug intervention. 3. 3. The authors investigated the voltage-dependent Ca ++ channel (VDCC) subtypes involved in somatic release of Substance P. Fresh ( + depolarising saline in the presence and absence of subtype selective VDCC blockers. Substance P released into the external media was collected and quantified using a radioimmunoassay. 4. 4. The results show that L-type and N-type, but not P-type, VDCCs play an important role in high K + evoked substance P release from rat DRG neurones.