Effect of Cholinergic Agonists on Muscle From Rodent Proximal and Distal Small Intestine

Thomas V. Nowak, Bonnie Harrington

Research output: Contribution to journalArticle

15 Scopus citations


Proximal and distal rat small intestine was cut into strips measuring 6.0 × 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, whereas those cut 90° to that axis were called circular strips. Stress in circular and longitudinal muscle strips was measured continuously as they were superf used with acetylcholine, carbamylcholine, methacholine, bethanechol, or physostigmine. Resting stress during stretch, acetylcholine-stimulated active stress, and total stress were determined. Proximal circular muscle was five times as sensitive to acetylcholine as distal circular muscle (p < 0.05); proximal longitudinal muscle was 2.8 times as sensitive to bethanechol as distal muscle (p < 0.05). Resting, active, and total stress were similar in proximal and distal muscle, but circular muscle showed nearly twice the resting stress of longitudinal muscle at either proximal or distal sites (p < 0.05). Physostigmine (10-6 M) increased acetylcholine-stimulated active stress in proximal and distal circular muscle by 29% and 70%, respectively (p < 0.05), but not in longitudinal muscle (p > 0.05). This difference between proximal and distal circular muscle (41%) was also significant (p < 0.05). Thus, the proximal and distal muscle of the rat small intestine differs in its sensitivity to various cholinergic agonists, but not in its length-stress properties.

Original languageEnglish (US)
Pages (from-to)1118-1125
Number of pages8
Issue number5
StatePublished - Jan 1 1985
Externally publishedYes


  • F
  • F
  • F
  • L
  • L
  • active stress
  • initial length
  • length at which a maximal active tension response occurs
  • resting stress
  • total stress

ASJC Scopus subject areas

  • Hepatology
  • Gastroenterology

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