Serotonergic excitatory drive to hypoglossal motoneurons in the decerebrate cat

Neurosci Lett. 1992 May 25;139(2):243-8. doi: 10.1016/0304-3940(92)90563-m.


In decerebrate, paralyzed, vagotomized and artificially ventilated cats, serotonin (5-HT) and its analogues, microinjected into the hypoglossal (XII) motor nucleus, altered the activity of the genioglossal branch of XII nerve. 5-HT, carboxamidotryptamine maleate (5-CT) and DOI (1-5 mM) increased the activity by over 200%. Methysergide reversed this increase. Methysergide, mianserin, or ketanserin (100-250 nl, 1 mM) reduced the spontaneous hypoglossal activity by 20-50%. Buspirone, 8-OH-DPAT and (-)-propranolol were without effect. Thus, 5-HT provides a substantial tonic excitatory drive to XII motoneurons. The 5-HT receptors involved are likely to be type 1C or 2, but uncertainty regarding the affinity profiles of the drugs used in in vivo conditions in the cat precludes a definite identification.

Publication types

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

MeSH terms

  • Animals
  • Cats
  • Decerebrate State / metabolism*
  • Female
  • Hypoglossal Nerve / metabolism*
  • Male
  • Microinjections
  • Motor Neurons / metabolism*
  • Respiration, Artificial
  • Serotonin / pharmacology
  • Serotonin / physiology*
  • Stimulation, Chemical
  • Vagotomy


  • Serotonin