Effect of sodium nitroprusside and 8-bromo cyclic GMP on nerve-mediated and acetylcholine-evoked secretory responses in the rat pancreas

Maria D. Yago, Jose A. Tapia, Gines M. Salido, Ernest Adeghate, Lubna M.O. Juma, Emilio Martinez-Victoria, Mariano Mañas, Jaipaul Singh

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

1. The effects of sodium nitroprusside (SNP) and 8-bromo-guanosine 3′5′ cyclic monophosphate (8-Br-cyclic GMP) on nerve-mediated and acetylcholine (ACh)-evoked amylase secretion, tritiated choline ([3H]-choline) release and on intracellular free calcium concentration ([Ca2+]i) in the isolated rat pancreas were investigated. 2. Electrical field stimulation (EFS; 10 Hz) and ACh (1 × 10-5 M) caused large increases in amylase output from pancreatic segments. The response to ACh was blocked by atropine (1 × 10-5 M) whereas the EFS-evoked response was markedly reduced but not abolished. In contrast, pretreatment with tetrodotoxin (1 × 10-6 M) abolished the secretory effect of EFS. 3. Either SNP (1 × 10-3 M) or 8-Br-cyclic GMP (1 × 10-4 M) inhibited amylase secretion compared to basal. Combining either SNP or 8-Br-cyclic GMP with EFS resulted in a marked decrease in amylase output compared to EFS alone. In contrast, either SNP or 8-Br-cyclic GMP had no significant effect on the amylase response to ACh. When extracellular Ca2+ concentration ([Ca2+]o) was elevated from 2.56 mM to 5.12 mM, SNP failed to inhibit the response to EFS. 4. EFS stimulated the release of 3H from pancreatic segments preloaded with [3H]-choline. Either SNP or 8-Br-cyclic GMP had no effect on basal 3H release but significantly reduced the EFS-evoked response. 5. In fura-2 loaded acinar cells, SNP elicited a small decrease in [Ca2+]i compared to basal and had no effect on the ACh-induced [Ca2+]i peak response. 6. Nitric oxide may modulate the release of endogenous neural ACh in response to EFS in the rat pancreas.

Original languageEnglish
Pages (from-to)49-56
Number of pages8
JournalBritish Journal of Pharmacology
Volume136
Issue number1
DOIs
Publication statusPublished - Jan 1 2002

Keywords

  • Acetylcholine
  • Amylase secretion
  • Calcium
  • Nerve stimulation
  • Neurotransmission
  • Nitric oxide
  • Pancreas
  • Sodium nitroprusside

ASJC Scopus subject areas

  • Pharmacology

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