Effects of muscarinic receptor stimulation and nitric oxide synthase inhibition on gastric tone and gastric myoelectrical activity in canines.
OBJECTIVE
This study was designed to assess whether the muscarinic receptor stimulation and nitric oxide synthase inhibition were equally effective on gastric fundic tone or gastric myoelectrical activity (GMA) in canines, and the correlation between gastric fundic tone and GMA.


METHODS
Gastric fundic tone and GMA were recorded on seven dogs implanted with serosal electrodes and a gastric cannula.


RESULTS
Bethanechol and L-nitro-N-arginine (L-NNA) significantly increased gastric fundic tone; gastric volume was decreased with bethanechol or L-NNA (P < 0.05). Increased spike activities were observed after both bethanechol and L-NNA. The percentage of slow waves superimposed with spikes was increased with bethanechol (P < 0.001) and L-NNA (P < 0.05). There was a significant reduction in dominant frequency (DF) (P < 0.05), dominant power (DP) (P < 0.05) and percentage of normal slow waves (%N) (P < 0.05) with bethanechol, while no significant change was observed with L-NNA. The variation of gastric tone was not correlated with parameters of GMA.


CONCLUSIONS
Muscarinic receptor stimulation and nitric oxide synthase inhibition have similar effects on gastric tone and gastric spike activities, but different effects on gastric slow waves. Gastric fundic tone does not correlate with gastric slow waves.
Chen
Jihong
J
Division of Gastroenterology, University of Texas Medical Branch, Galveston, Texas 77555-0632, USA.
Xing
Jinhong
J
Chen
Jiande D Z
JD
D000704:Analysis of Variance; D000818:Animals; D018723:Bethanechol / Q000494:pharmacology; D004285:Dogs; D004558:Electric Stimulation; D005260:Female; D009129:Muscle Tonus / Q000187:drug effects / Q000502:physiology; D016065:Myoelectric Complex, Migrating / Q000187:drug effects* / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D019335:Nitroarginine / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000502:physiology*; D013270:Stomach / Q000187:drug effects* / Q000502:physiology*
D011976:Receptors, Muscarinic; D018723:Bethanechol; D019335:Nitroarginine; D019001:Nitric Oxide Synthase