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A functional medial preoptic nucleus (MPO) is required for scrotal thermal stimuli to alter the neuronal activity of thermoresponsive ventromedial hypothalamic (VMH) neurons.

Publication ,  Journal Article
Li, Q; Thornhill, J
Published in: Brain research
April 1996

Thermoresponsiveness of ventromedial hypothalamic (VMH) neurons to scrotal thermal stimulation was determined before and after microinjection of lidocaine into the medial preoptic nucleus (MPO). Male, urethane anesthetized Sprague-Dawley rats, maintained colonically at 37 degrees C had VMH extracellular neuronal activity recorded following 3 cycles of scrotal thermal stimulation (localized, incremental heating and cooling, between 10 and 40 degrees C). Based on their thermal coefficients (TC), warm (WRN), cold (CRN) thermoresponsive and temperature non-responsive (TNRN) VMH neurons had their neuronal activity recorded following each cycle of scrotal thermal stimulation before and after MPO injections of sterile saline (300 nl volume) or 2% buffered lidocaine (200 ng). Thermoresponsiveness of all warm and cold VMH neurons to scrotal thermal stimulation was blocked by prior lidocaine administration into the MPO, effects that were reversed approximately 60 min after. However, MPO lidocaine administration caused no significant change in the thermal coefficients of VMH TNRNs to scrotal thermal stimulation. Results infer that a functional MPO is required for thermal afferent signals arising from the scrotum to reach thermoresponsive VMH neurons.

Duke Scholars

Published In

Brain research

DOI

EISSN

1872-6240

ISSN

0006-8993

Publication Date

April 1996

Volume

716

Issue

1-2

Start / End Page

134 / 140

Related Subject Headings

  • Ventromedial Hypothalamic Nucleus
  • Thermoreceptors
  • Scrotum
  • Rats, Sprague-Dawley
  • Rats
  • Preoptic Area
  • Neurons, Efferent
  • Neurology & Neurosurgery
  • Microinjections
  • Male
 
Journal cover image

Published In

Brain research

DOI

EISSN

1872-6240

ISSN

0006-8993

Publication Date

April 1996

Volume

716

Issue

1-2

Start / End Page

134 / 140

Related Subject Headings

  • Ventromedial Hypothalamic Nucleus
  • Thermoreceptors
  • Scrotum
  • Rats, Sprague-Dawley
  • Rats
  • Preoptic Area
  • Neurons, Efferent
  • Neurology & Neurosurgery
  • Microinjections
  • Male