title: Differential Ca(2+) signaling characteristics of inhibitory and excitatory myenteric motor neurons in culture.
abstract: Physiological studies on functionally identified myenteric neurons are scarce because of technical limitations. We combined retrograde labeling, cell culturing, and fluorescent intracellular Ca(2+) concentration ([Ca(2+)](i)) signaling to study excitatory neurotransmitter responsiveness of myenteric motor neurons. 1, 1-Didodecyl-3,3,3',3'-tetramethyl indocarbocyanine (DiI) was used to label circular muscle motor neurons of the guinea pig ileum. DiI-labeled neurons were easily detectable in cultures prepared from these segments. The excitatory neurotransmitters (10(-5) M) acetylcholine, substance P, and serotonin induced a transient rise in [Ca(2+)](i) in subsets of DiI-labeled neurons (66.7, 56.5, and 84. 3%, respectively). DiI-labeled motor neurons were either inhibitory (23.8%) or excitatory (76.2%) as assessed by staining for nitric oxide synthase or choline acetyltransferase. Compared with excitatory motor neurons, significantly fewer inhibitory neurons in culture responded to acetylcholine (0 vs. 69%) and substance P (12.5 vs. 69.2%). We conclude that combining retrograde labeling and Ca(2+) imaging allows identification of differential receptor expression in functionally identified neurons in culture.
authors.affiliation: Center for Gastroenterological Research, Katholieke Universiteit Leuven, B-3000 Leuven, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Vanden Berghe
authors.forename: S
authors.initials: S
authors.lastname: Molhoek
authors.forename: L
authors.initials: L
authors.lastname: Missiaen
authors.forename: J
authors.initials: J
authors.lastname: Tack
authors.forename: J
authors.initials: J
authors.lastname: Janssens
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology*; D002232:Carbocyanines; D002478:Cells, Cultured; D005260:Female; D005456:Fluorescent Dyes; D006168:Guinea Pigs; D008297:Male; D018613:Microscopy, Confocal; D009046:Motor Neurons / Q000166:cytology* / Q000502:physiology*; D009130:Muscle, Smooth / Q000294:innervation; D009197:Myenteric Plexus / Q000166:cytology*; D009433:Neural Inhibition / Q000502:physiology; D011188:Potassium / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
chemical_list: C035005:3,3'-dihexadecylindocarbocyanine; D002232:Carbocyanines; D005456:Fluorescent Dyes; D014665:Vasodilator Agents; D012701:Serotonin; D013373:Substance P; D000109:Acetylcholine; D011188:Potassium