Neither peripheral nerve input nor cortical NMDA receptor activity are necessary for recovery of a disrupted barrel pattern in rat somatosensory cortex

Brain Res Dev Brain Res. 2001 Jul 23;129(1):95-106. doi: 10.1016/s0165-3806(01)00163-8.

Abstract

Elevating cortical serotonin (5-HT) in rats from postnatal day (P-) 0 to P-6 by administering the monoamine oxidase (MAO(A)) inhibitor, clorgyline, produces a dose-dependent spectrum of effects on rat somatosensory organization, ranging from enlarged with indistinct septa to a complete lack of vibrissae-related patterns. However, if clorgyline treatment is stopped on P-6, a qualitatively and quantitatively normal vibrissae-related pattern of thalamocortical afferents appears in somatosensory cortex (S-I) on P-10. We employed high performance liquid chromatography (HPLC), infraorbital nerve (ION) transection, N-methyl-D-aspartate (NMDA) receptor blockade, 1,1'-dioctadecyl-3,3,3"3'-tetramethylindocarbocyanine perchlorate (DiI) labeling of thalamic afferents, and CO histochemistry to determine whether peripheral nerve input and/or cortical NMDA receptor activity were required for the recovery of vibrissae-related patterns in clorgyline-treated animals. Clorgyline administration from P-0 to P-6 produced a 1589.4+/-53.3% increase in cortical 5-HT over control animals on P-6 and a 268.8+/-6.3% elevation over controls at P-10. Postnatal day 6 pups had significantly altered vibrissae-related patterns in S-I following 6 days of clorgyline treatment but by P-10, the characteristic vibrissae-related patterns were restored. Neither transection of the ION nor application of the NMDA antagonist, DL-2-amino-5-phosphonovaleric acid (APV), to the cortices of P-6 pups that were treated with clorgyline from birth had any significant effect on the recovery of the vibrissae-related patterns by P-10. These results indicate that neither peripheral nerve input nor cortical NMDA receptor activity are necessary for the restoration of cortical vibrissae-related patterns in rats that have sustained transient elevations of 5-HT.

Publication types

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

MeSH terms

  • 2-Amino-5-phosphonovalerate / pharmacology
  • Animals
  • Animals, Newborn
  • Autoradiography
  • Brain Stem / cytology
  • Brain Stem / drug effects
  • Brain Stem / growth & development
  • Carbocyanines
  • Chromatography, High Pressure Liquid
  • Clorgyline / pharmacology
  • Denervation
  • Dizocilpine Maleate / pharmacology
  • Excitatory Amino Acid Antagonists / pharmacology
  • Female
  • Fluorescent Dyes
  • Iodine Radioisotopes
  • Male
  • Maxillary Nerve / cytology*
  • Maxillary Nerve / physiology*
  • Monoamine Oxidase Inhibitors / pharmacology
  • Neurons, Afferent / physiology
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, N-Methyl-D-Aspartate / antagonists & inhibitors
  • Receptors, N-Methyl-D-Aspartate / metabolism*
  • Serotonin / metabolism
  • Somatosensory Cortex / cytology*
  • Somatosensory Cortex / drug effects
  • Somatosensory Cortex / growth & development*
  • Thalamus / cytology
  • Thalamus / drug effects
  • Thalamus / growth & development
  • Vibrissae / innervation

Substances

  • 3,3'-dihexadecylindocarbocyanine
  • Carbocyanines
  • Excitatory Amino Acid Antagonists
  • Fluorescent Dyes
  • Iodine Radioisotopes
  • Monoamine Oxidase Inhibitors
  • Receptors, N-Methyl-D-Aspartate
  • Serotonin
  • Dizocilpine Maleate
  • 2-Amino-5-phosphonovalerate
  • Clorgyline