Effect of immune sensitization on stimulated ACh release from trachealis muscle in vitro

Am J Physiol. 1993 Jul;265(1 Pt 1):L13-8. doi: 10.1152/ajplung.1993.265.1.L13.

Abstract

We assessed the effect of immune sensitization on acetylcholine (ACh) release from parasympathetic nerve terminals in tracheal smooth muscle (TSM) strips from ragweed-sensitized (RWS) and sham-sensitized, littermate control (LMC) dogs. Strips of TSM were tethered to force transducers at optimal length in perfusion chambers containing [3H]choline and a fixed volume of physiological perfusate. Tissues were equilibrated for 1 h by electrical field stimulation (EFS) every 5 min to facilitate uptake of label into parasympathetic nerves as ACh. Fresh perfusate (containing 3 x 10(-8) M physostigmine) was collected at 5-min intervals for 1 h, and a rate coefficient of [3H]ACh release was determined. Tissues were exposed to agonists in the seventh collection period, and the increase in label release (ratio change where < or = 1.00 = baseline) and force production were determined. Ragweed antigen challenge stimulated [3H]ACh release and contraction in RWS but not LMC tissues. [3H]ACh release was 1.93 +/- 0.22 x baseline in RWS vs. 0.92 +/- 0.02 in control tissues (P < 0.01); contraction was 31.2 +/- 9.5% of that elicited by EFS (% EFS) in RWS vs. 0% EFS in LMC tissues (P < 0.01). Strips of TSM from RWS but not LMC dogs demonstrated concentration-dependent, augmented release of ACh caused by histamine. After 10(-4) M histamine, [3H]ACh release in RWS was 1.94 +/- 0.37 x baseline vs. 1.05 +/- 0.06 for LMC tissues (P < 0.05); histamine also caused greater contraction in RWS (106.5 +/- 5.9% EFS) vs. LMC (86.5 +/- 5.6% EFS; P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylcholine / metabolism*
  • Animals
  • Antigens / immunology
  • Dogs
  • Electric Stimulation
  • Histamine / pharmacology
  • Immunization*
  • Muscle, Smooth / immunology
  • Muscle, Smooth / metabolism*
  • Osmolar Concentration
  • Pharmaceutical Vehicles
  • Pollen / immunology
  • Stimulation, Chemical
  • Trachea / immunology
  • Trachea / metabolism*

Substances

  • Antigens
  • Pharmaceutical Vehicles
  • Histamine
  • Acetylcholine