Actions of neuropeptide K and calcitonin gene-related peptide on inferior mesenteric ganglion cells--tachykinin interactions with non-cholinergic potentials evoked by ureteric nerve stimulation.
Neuropeptide K (NPK) induced a slow depolarization in principal ganglion cells of the guinea pig inferior mesenteric ganglion (IMG) in vitro. This effect was due to a postsynaptic action and prevented by pre-exposure of the IMG to neurokinin A (NKA) or substance P (SP). The non-cholinergic slow postsynaptic excitatory potential (s-EPSP) evoked by ureteric nerve stimulation was depressed during NPK, SP or NKA application. Calcitonin gene-related peptide (CGRP) applied in concentrations up to 10 microM had no effect on the membrane potential in 90% of IMG cells nor did it influence the s-EPSP. We suggest that NPK may depolarize IMG neurones via similar mechanisms/in a similar fashion, to other tachykinins and that the s-EPSP, induced by stimulation of the afferent ureteric nerve fibres, is mediated by a tachykinin whereas there is little indication/evidence for an involvement of CGRP.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D015740:Calcitonin Gene-Related Peptide; D004558:Electric Stimulation; D005724:Ganglia / Q000187:drug effects / Q000502:physiology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D008643:Mesentery / Q000187:drug effects / Q000294:innervation* / Q000502:physiology; D015288:Neurokinin A; D009479:Neuropeptides / Q000494:pharmacology*; D010525:Peripheral Nerves / Q000187:drug effects / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000502:physiology; D013373:Substance P / Q000494:pharmacology; D015320:Tachykinins
D009479:Neuropeptides; D011950:Receptors, Cholinergic; D015320:Tachykinins; C045206:neuropeptide K; D013373:Substance P; D015288:Neurokinin A; D015740:Calcitonin Gene-Related Peptide