Augmentation of parasympathetic contraction in tracheal and bronchial airways by PGF2 alpha in situ

J Appl Physiol (1985). 1985 May;58(5):1558-64. doi: 10.1152/jappl.1985.58.5.1558.

Abstract

We studied the effect of exogenous prostaglandin F2 alpha (PGF2 alpha) on airway smooth muscle contraction caused by parasympathetic stimulation in 22 mongrel dogs in situ. Voltage (0-30 V, constant 20 Hz) and frequency-response (0-25 Hz, 25 V) curves were generated by stimulating the cut ends of both cervical vagus nerves. Airway response was measured isometrically as active tension (AT) in a segment of cervical trachea and as change in airway resistance (RL) and dynamic compliance (Cdyn) in bronchial airways. One hour after 5 mg/kg iv indomethacin, a cumulative frequency-response curve was generated in nine animals by electrical stimulation of the vagus nerves at 15-s intervals. Reproducibility was demonstrated by generating a second curve 7 min later. A third frequency-response curve was generated during active contraction of the airway caused by continuous intravenous infusion of 10 micrograms X kg-1 X min-1PPGF2 alpha. Additional frequency-response studies were generated 15 and 30 min after PGF2 alpha, when airway contractile response (delta RL = +2.8 +/- 0.65 cmH2O X 1(-1) X s; delta Cdyn = -0.0259 +/- 0.007 1/cmH2O) returned to base line. Substantial augmentation of AT, RL, and Cdyn responses was demonstrated in every animal studied (P less than 0.01 for all points greater than 8 Hz) 15 min after PGF2 alpha. At 30 min, response did not differ from initial base-line control. In four animals receiving sham infusion, all frequency-response curves were identical. We demonstrate that PGF2 alpha augments the response to vagus nerve stimulation in tracheal and bronchial airways. Augmentation does not depend on PGF2 alpha-induced active tone.

Publication types

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

MeSH terms

  • Animals
  • Bronchi / innervation
  • Bronchi / physiology*
  • Dinoprost
  • Dogs
  • Electric Stimulation
  • Female
  • Indomethacin / pharmacology
  • Male
  • Muscle Contraction / drug effects*
  • Muscle, Smooth / drug effects
  • Muscle, Smooth / physiology*
  • Parasympathetic Nervous System / physiology*
  • Prostaglandins F / pharmacology*
  • Stimulation, Chemical
  • Trachea / innervation
  • Trachea / physiology*
  • Vagus Nerve / physiology

Substances

  • Prostaglandins F
  • Dinoprost
  • Indomethacin