title: Dual purinergic synaptic transmission in the human enteric nervous system.
abstract: Based on findings in rodents, we sought to test the hypothesis that purinergic modulation of synaptic transmission occurs in the human intestine. Time series analysis of intraneuronal free Ca(2+) levels in submucosal plexus (SMP) from Roux-en-Y specimens was done using Zeiss LSM laser-scanning confocal fluo-4 AM Ca(2+) imaging. A 3-s fiber tract stimulation (FTS) was used to elicit a synaptic Ca(2+) response. Short-circuit current (I(sc) = chloride secretion) was recorded in mucosa-SMP in flux chambers. A distension reflex or electrical field stimulation was used to study I(sc) responses. Ca(2+) imaging was done in 1,222 neurons responding to high-K(+) depolarization from 61 surgical cases. FTS evoked synaptic Ca(2+) responses in 62% of recorded neurons. FTS caused frequency-dependent Ca(2+) responses (0.1-100 Hz). FTS Ca(2+) responses were inhibited by Omega-conotoxin (70%), hexamethonium (50%), TTX, high Mg(2+)/low Ca(2+) (< or = 100%), or capsaicin (25%). A P2Y(1) receptor (P2Y(1)R) antagonist, MRS-2179 or PLC inhibitor U-73122, blocked FTS responses (75-90%). P2Y(1)R-immunoreactivity occurred in 39% of vasoactive intestinal peptide-positive neurons. The selective adenosine A(3) receptor (AdoA(3)R) agonist 2-chloro-N(6)-(3-iodobenzyl)adenosine-5'-N-methylcarboxamide (2-Cl-IBMECA) caused concentration- and frequency-dependent inhibition of FTS Ca(2+) responses (IC(50) = 8.5 x 10(-8) M). The AdoA(3)R antagonist MRS-1220 augmented such Ca(2+) responses; 2-Cl-IBMECA competed with MRS-1220. Knockdown of AdoA(1)R with 8-cyclopentyl-3-N-(3-{[3-(4-fluorosulphonyl)benzoyl]-oxy}-propyl)-1-N-propyl-xanthine did not prevent 2-Cl-IBMECA effects. MRS-1220 caused 31% augmentation of TTX-sensitive distension I(sc) responses. The SMP from Roux-en-Y patients is a suitable model to study synaptic transmission in human enteric nervous system (huENS). The P2Y(1)/Galphaq/PLC/inositol 1,3,5-trisphosphate/Ca(2+) signaling pathway, N-type Ca(2+) channels, nicotinic receptors, and extrinsic nerves contribute to neurotransmission in huENS. Inhibitory AdoA(3)R inhibit nucleotide or cholinergic transmission in the huENS.
authors: Department of Anesthesiology, College of Medicine and Public Health, The Ohio State University, Columbus, OH 43210, USA.
authors: J E
authors: JE
authors: Wunderlich
authors: B J
authors: BJ
authors: Needleman
authors: Z
authors: Z
authors: Chen
authors: J G
authors: JG
authors: Yu
authors: Y
authors: Y
authors: Wang
authors: I
authors: I
authors: Grants
authors: D J
authors: DJ
authors: Mikami
authors: W S
authors: WS
authors: Melvin
authors: H J
authors: HJ
authors: Cooke
authors: F L
authors: FL
authors: Christofi
mesh_terms: D000814:Aniline Compounds; D002118:Calcium / Q000378:metabolism; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism; D004558:Electric Stimulation; D017615:Enteric Nervous System / Q000187:drug effects / Q000502:physiology*; D005456:Fluorescent Dyes; D006801:Humans; D018613:Microscopy, Confocal; D009412:Nerve Fibers / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009765:Obesity / Q000378:metabolism; D011799:Quinazolines / Q000494:pharmacology; D011983:Receptors, Purinergic / Q000187:drug effects / Q000502:physiology*; D018048:Receptors, Purinergic P2 / Q000502:physiology; D058472:Receptors, Purinergic P2Y1; D013368:Submucous Plexus / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D014230:Triazoles / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism; D014966:Xanthenes
chemical_list: C110041:9-chloro-2-(2-furyl)-5-phenylacetylamino(1,2,4)triazolo(1,5-c)quinazoline; D000814:Aniline Compounds; D018118:Chloride Channels; C409648:Fluo 4; D005456:Fluorescent Dyes; C546382:P2RY1 protein, human; D011799:Quinazolines; D011983:Receptors, Purinergic; D018048:Receptors, Purinergic P2; D058472:Receptors, Purinergic P2Y1; D014230:Triazoles; D014966:Xanthenes; D014660:Vasoactive Intestinal Peptide; D010738:Type C Phospholipases; D002118:Calcium