Carbachol injection into the pontine reticular formation depresses laryngeal muscle activities and airway reflexes in decerebrate cats

Neurosci Res. 2010 May;67(1):40-50. doi: 10.1016/j.neures.2010.01.009. Epub 2010 Feb 6.


To understand the role of cholinoceptive, medial pontine reticular formation (mPRF) neurons in the control of upper airway, pharyngolaryngeal reflexes, we measured activities of intrinsic laryngeal muscles (posterior cricoarytenoid, PCA; thyroarytenoid, TA), diaphragm (DIA), genioglossus (GG) and a neck muscle (trapezius) in unanesthetized, decerebrated, spontaneously breathing cats with and without mPRF carbachol injections. The ethimoidal nerve was electrically stimulated to evoke sneezing, and the superior laryngeal nerve to evoke the laryngeal reflex, swallowing, and coughing. Carbachol reduced the amplitudes of the spontaneous electromyographic activities in the neck, TA, PCA, GG, and DIA to 7%, 30%, 54%, 45% and 71% of control, respectively, reduced the respiratory rate to 53% without changes in expiratory CO(2) concentration; the magnitude of the laryngeal reflex in the TA muscle to 56%; increased its latency by 13%; and reduced the probability of stimulus-induced sneezing, swallowing, and coughing to less than 40%. These changes lasted more than 1h. These data demonstrate that important upper airway reflexes are suppressed by increasing cholinergic neurotransmission in the mPRF. Because acetylcholine release in the mPRF changes in accordance with sleep-wake cycles, the present findings are relevant to the control of upper airway reflexes during various vigilance states.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carbachol / pharmacology*
  • Cats
  • Cholinergic Agonists / pharmacology*
  • Cough / physiopathology
  • Decerebrate State
  • Deglutition / drug effects
  • Electric Stimulation
  • Electromyography
  • Female
  • Laryngeal Muscles / drug effects*
  • Laryngeal Muscles / physiology
  • Laryngeal Nerves / physiology
  • Larynx / drug effects
  • Larynx / physiology
  • Male
  • Neck Muscles / drug effects
  • Neck Muscles / physiology
  • Pharynx / drug effects*
  • Pharynx / innervation
  • Pharynx / physiology
  • Pons / drug effects*
  • Pons / physiology
  • Reflex / drug effects*
  • Reticular Formation / drug effects*
  • Reticular Formation / physiology
  • Sneezing / drug effects


  • Cholinergic Agonists
  • Carbachol