Tachykinin-induced responses via neurokinin-1 and -3 receptors in hamster submandibular ganglion neurones.
Both substance P and neurokinin A are known as neurotransmitters of the submandibular ganglion cell. In this study, the effects of neurokinin (NK) receptor-subtype agonists on hamster submandibular ganglion cells were investigated using the whole-cell patch-clamp technique. Membrane currents evoked by a ramp pulse from +50 to -100 mV (-150 mV/1000 msec) were compared in both the absence and presence of NK receptor agonist. The NK-1 receptor agonist [Sar9, Met (O2)11]-substance P, the NK-2 receptor agonist [Ala5, beta-Ala8]-alpha-neurokinin fragment 4-10, and the NK-3 receptor agonist senktide were used. The three agonists dose-dependently increased the amplitude of the inward current with a reversal potential near 0 mV. Their rank order was NK-1 = NK-3 > NK-2. Even when the external solution was replaced with Cs+ or N-methyl-D-glucamine+ instead of Na+, the NK receptor agonists also increased the amplitude of the inward current. Thus, NK-1 and NK-3 receptors are apparently coupled with non-selective cation channels in submandibular ganglion cells.
Soejima
T
T
Department of Physiology, Tokyo Dental College, Chiba, Japan.
Endoh
T
T
Suzuki
T
T
D000818:Animals; D002478:Cells, Cultured; D002586:Cesium / Q000494:pharmacology; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D005724:Ganglia / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects / Q000378:metabolism; D008297:Male; D008536:Meglumine / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D064729:Neurokinin-1 Receptor Antagonists; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D018408:Patch-Clamp Techniques; D018040:Receptors, Neurokinin-1 / Q000819:agonists / Q000378:metabolism*; D018041:Receptors, Neurokinin-2 / Q000819:agonists / Q000378:metabolism; D018042:Receptors, Neurokinin-3 / Q000819:agonists / Q000378:metabolism*; D013363:Submandibular Gland / Q000294:innervation*; D013373:Substance P / Q000037:antagonists & inhibitors; D015320:Tachykinins / Q000494:pharmacology*; D013997:Time Factors
D007473:Ion Channels; D064729:Neurokinin-1 Receptor Antagonists; D018040:Receptors, Neurokinin-1; D018041:Receptors, Neurokinin-2; D018042:Receptors, Neurokinin-3; D015320:Tachykinins; D002586:Cesium; D013373:Substance P; D008536:Meglumine