title: VIP inhibits high voltage-gated calcium channel currents of hamster submandibular ganglion neurons.
abstract: In this study, we investigated the modulation of calcium channels by vasoactive intestinal polypeptide (VIP) in hamster submandibular ganglion (SMG) cells using the whole-cell patch clamp technique. VIP (1 microM) inhibited the high voltage-gated calcium channels in the SMG neurons via activation of VIP receptors and G-protein coupled to these receptors, but did not affect the low voltage-gated calcium channels. VIP at 1 microM reduced the peak amplitude of the maximum high voltage-gated calcium current by 26.0 +/- 6.2% (mean +/- S.E., n = 5) and slowed the rising phase of the calcium current. The time to peak of the maximum high voltage-gated calcium current was prolonged from 16.8 msec to 22.4 msec. In a representative cell, 1 microM VIP reduced the peak amplitude of maximum high voltage-gated calcium current by 50.5% and the amplitude at the end of voltage step after 300 msec by 51.9%. The VIP-induced inhibition of the calcium current was produced in a voltage-dependent manner. Inhibition was maximal (50.5%) at the level of -20 mV. Therefore, VIP inhibits both transient and sustained types of high voltage-gated calcium channels in the hamster SMG neuron.
authors.affiliation: Department of Physiology, Tokyo Dental College, Chiba, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hayashi
authors.forename: T
authors.initials: T
authors.lastname: Endoh
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects* / Q000502:physiology; D006224:Cricetinae; D004553:Electric Conductivity; D005726:Ganglia, Parasympathetic / Q000187:drug effects / Q000502:physiology; D008297:Male; D018408:Patch-Clamp Techniques; D013363:Submandibular Gland / Q000294:innervation*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D014660:Vasoactive Intestinal Peptide