Inhibition of rostral medullary raphé neurons prevents cold-induced activity in sympathetic nerves to rat tail and rabbit ear arteries

Youichirou Ootsuka; William W Blessing; Robin M McAllen

doi:10.1016/j.neulet.2003.11.067

Inhibition of rostral medullary raphé neurons prevents cold-induced activity in sympathetic nerves to rat tail and rabbit ear arteries

Neurosci Lett. 2004 Feb 26;357(1):58-62. doi: 10.1016/j.neulet.2003.11.067.

Authors

Youichirou Ootsuka¹, William W Blessing, Robin M McAllen

Affiliation

¹ Department of Human Physiology, School of Medicine, Centre for Neuroscience, Flinders University, Bedford Park, SA 5042, Australia. yoichiro.otsuka@flinders.edu.au

PMID: 15036613
DOI: 10.1016/j.neulet.2003.11.067

Abstract

Sympathetically-mediated vasoconstriction of cutaneous vessels is critical for thermoregulation in the cold. We determined whether cold-induced sympathetic discharge depends on activity of neurons in the rostral medullary raphé. In urethane-anesthetized rats and rabbits, cooling the trunk skin by a water jacket reproducibly increased cutaneous sympathetic discharge recorded in the tail (rats) and the ear pinna (rabbits). When neurons in the rostral medullary raphé were inhibited by microinjection of glycine (30-100 nmol in 60-200 nl in rats), or muscimol (1 nmol in 100 nl in rabbits), cutaneous sympathetic activity was silenced and no longer responded to cooling (7+/-3 and 5+/-2% of pre-injection increase in rats and rabbits, respectively, P < 0.01). Our data demonstrate that activity of rostral medullary raphé neurons is important for the CNS mediation of cold-induced increases in sympathetic cutaneous vasomotor nerves.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Action Potentials / drug effects
Action Potentials / physiology
Animals
Arteries / innervation*
Arteries / physiology
Blood Pressure / drug effects
Blood Pressure / physiology
Body Temperature / drug effects
Body Temperature / physiology
Body Temperature Regulation / drug effects
Body Temperature Regulation / physiology
Cold Temperature / adverse effects
Ear / blood supply
Ear / physiology
GABA Agonists / pharmacology
Glycine / pharmacology
Male
Medulla Oblongata / cytology
Medulla Oblongata / drug effects
Medulla Oblongata / physiology*
Muscimol / pharmacology
Neural Inhibition / drug effects
Neural Inhibition / physiology
Neurons / physiology
Rabbits
Raphe Nuclei / cytology
Raphe Nuclei / drug effects
Raphe Nuclei / physiology*
Rats
Rats, Sprague-Dawley
Regional Blood Flow / drug effects
Regional Blood Flow / physiology*
Skin / blood supply
Sympathetic Fibers, Postganglionic / physiology*
Tail / blood supply
Tail / physiology
Vasomotor System / drug effects
Vasomotor System / physiology*

Substances

GABA Agonists
Muscimol
Glycine