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Enhancement of EFS-induced contractions, by agmatine, in guinea pig gallbladder smooth muscle strips.
J Gastroenterol. 2005 May; 40(5):498-503.JG

Abstract

BACKGROUND

Electrical field stimulation of gallbladder muscle strips produces frequency-dependent contractions by activating cholinergic nerves. The cholinergic motor function of the gallbladder and enteric system is also modulated by other mediators. The aim of this study was to investigate the role of agmatine, a ligand for alpha 2-adrenoceptors and imidazoline binding sites, in the cholinergic motor activity of guinea pig gallbladder smooth muscle.

METHODS

Gallbladder muscle strips obtained from guinea pigs were subjected to electrical field stimulation (1-64 Hz, 100 V, 1-ms pulse width, and 10-s train duration). Frequency-response contractions of gallbladder muscle strips were traced before and after the addition of cumulative concentrations of agmatine (10(-5)-10(-3) M) to the tissue bath. The same set of experiments was repeated in the presence of different antagonists.

RESULTS

Agmatine by itself did not produce any contractions in guinea pig gallbladder muscle strips, but significantly enhanced the contractile response produced by electrical field stimulation. Yohimbine (10(-6) M), a selective alpha 2-adrenergic blocker, neither decreased nor increased the enhancement induced by agmatine. However, idazoxan (10(-4) M), an alpha-receptor blocker and imidazoline receptor antagonist, abolished this enhanced contractile response. Pretreatment with N(W)-nitro L-arginine methyl ester (L-NAME; 30 microM), and indomethacin (10 microM) did not inhibit the effect of agmatine.

CONCLUSIONS

Our findings indicate that agmatine has a modulator role in the electrical field stimulation-induced cholinergic contractions of guinea pig gallbladder smooth muscle strips, and this role could be mediated by imidazoline receptors. Receptor binding studies should be done to determine the presence of endogenous agmatine and imidazoline receptors in gallbladder smooth muscle.

Authors+Show Affiliations

Department of Pharmacology, Cumhuriyet University Medical School, 58140, Sivas, Turkey.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15942715

Citation

Yildirim, Sahin, et al. "Enhancement of EFS-induced Contractions, By Agmatine, in Guinea Pig Gallbladder Smooth Muscle Strips." Journal of Gastroenterology, vol. 40, no. 5, 2005, pp. 498-503.
Yildirim S, Aydin C, Koyuncu A, et al. Enhancement of EFS-induced contractions, by agmatine, in guinea pig gallbladder smooth muscle strips. J Gastroenterol. 2005;40(5):498-503.
Yildirim, S., Aydin, C., Koyuncu, A., Bagcivan, I., Sarac, B., & Sarioglu, Y. (2005). Enhancement of EFS-induced contractions, by agmatine, in guinea pig gallbladder smooth muscle strips. Journal of Gastroenterology, 40(5), 498-503.
Yildirim S, et al. Enhancement of EFS-induced Contractions, By Agmatine, in Guinea Pig Gallbladder Smooth Muscle Strips. J Gastroenterol. 2005;40(5):498-503. PubMed PMID: 15942715.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Enhancement of EFS-induced contractions, by agmatine, in guinea pig gallbladder smooth muscle strips. AU - Yildirim,Sahin, AU - Aydin,Cengiz, AU - Koyuncu,Ayhan, AU - Bagcivan,Ihsan, AU - Sarac,Bulent, AU - Sarioglu,Yusuf, PY - 2003/08/06/received PY - 2005/02/07/accepted PY - 2005/6/9/pubmed PY - 2005/10/19/medline PY - 2005/6/9/entrez SP - 498 EP - 503 JF - Journal of gastroenterology JO - J. Gastroenterol. VL - 40 IS - 5 N2 - BACKGROUND: Electrical field stimulation of gallbladder muscle strips produces frequency-dependent contractions by activating cholinergic nerves. The cholinergic motor function of the gallbladder and enteric system is also modulated by other mediators. The aim of this study was to investigate the role of agmatine, a ligand for alpha 2-adrenoceptors and imidazoline binding sites, in the cholinergic motor activity of guinea pig gallbladder smooth muscle. METHODS: Gallbladder muscle strips obtained from guinea pigs were subjected to electrical field stimulation (1-64 Hz, 100 V, 1-ms pulse width, and 10-s train duration). Frequency-response contractions of gallbladder muscle strips were traced before and after the addition of cumulative concentrations of agmatine (10(-5)-10(-3) M) to the tissue bath. The same set of experiments was repeated in the presence of different antagonists. RESULTS: Agmatine by itself did not produce any contractions in guinea pig gallbladder muscle strips, but significantly enhanced the contractile response produced by electrical field stimulation. Yohimbine (10(-6) M), a selective alpha 2-adrenergic blocker, neither decreased nor increased the enhancement induced by agmatine. However, idazoxan (10(-4) M), an alpha-receptor blocker and imidazoline receptor antagonist, abolished this enhanced contractile response. Pretreatment with N(W)-nitro L-arginine methyl ester (L-NAME; 30 microM), and indomethacin (10 microM) did not inhibit the effect of agmatine. CONCLUSIONS: Our findings indicate that agmatine has a modulator role in the electrical field stimulation-induced cholinergic contractions of guinea pig gallbladder smooth muscle strips, and this role could be mediated by imidazoline receptors. Receptor binding studies should be done to determine the presence of endogenous agmatine and imidazoline receptors in gallbladder smooth muscle. SN - 0944-1174 UR - https://www.unboundmedicine.com/medline/citation/15942715/Enhancement_of_EFS_induced_contractions_by_agmatine_in_guinea_pig_gallbladder_smooth_muscle_strips_ L2 - https://dx.doi.org/10.1007/s00535-005-1575-2 DB - PRIME DP - Unbound Medicine ER -