Purinergic nerves mediate the non-nitrergic relaxation of the human ileum in response to electrical field stimulation.
There has been no direct functional evidence for a purinergic innervation of the human intestinal muscle. In the present study, the relaxant effects of electrical field stimulation (1 or 10 Hz for 20s), ATP, and isoprenaline were studied in organ bath experiments on precontracted circular muscle strips of the human ileum. Non-adrenergic, non-cholinergic relaxations in response to electrical field stimulation in the presence of a nitric oxide synthase inhibitor were significantly reduced by the P(2) purinoceptor antagonists pyridoxal-phosphate-6-azophenyl-2',4'-disulphonic acid (PPADS; 50 microM) or suramin (100 microM). A combination of the two antagonists yielded an approximately 70% inhibition at 1 Hz. The relaxant effect of exogenous ATP, but not that of isoprenaline, was inhibited by PPADS+suramin. It is concluded that purinergic nerves (through P(2) purinoceptors) play a mediating role in the non-nitrergic relaxation in the human ileum.
Undi
Sarolta
S
Department of Pharmacology and Pharmacotherapy, University Medical School of Pécs, Szigeti u 12, H-7643 Pécs, Hungary.
Benkó
Rita
R
Wolf
Matyas
M
Illényi
Laszlo
L
Horváth
Ors Peter
OP
Antal
Andras
A
Csontos
Zsolt
Z
Vereczkei
Andras
A
Barthó
Lorand
L
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D004558:Electric Stimulation; D017615:Enteric Nervous System / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007082:Ileum / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D007545:Isoproterenol / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000294:innervation / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D058919:Purinergic P2 Receptor Antagonists; D011687:Purines / Q000378:metabolism*; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D013498:Suramin / Q000494:pharmacology
D000318:Adrenergic beta-Agonists; D004791:Enzyme Inhibitors; D058919:Purinergic P2 Receptor Antagonists; D011687:Purines; D018048:Receptors, Purinergic P2; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; D009569:Nitric Oxide; D011732:Pyridoxal Phosphate; D013498:Suramin; D000255:Adenosine Triphosphate; D019001:Nitric Oxide Synthase; D007545:Isoproterenol