Effect of neonatal axoplasmic transport attenuation in the infraorbital nerve on vibrissae-related patterns in the rat's brainstem, thalamus and cortex

Eur J Neurosci. 1996 Aug;8(8):1601-12. doi: 10.1111/j.1460-9568.1996.tb01305.x.

Abstract

This study evaluated the effects of neonatal attenuation of axoplasmic transport in the infraorbital nerve (ION) on the organization of vibrissae-related patterns in the rat's CNS. Application of colchicine- or vinblastine- impregnated implants to the ION from birth until postnatal day (P)6 to P10 resulted in a 92.4% reduction in the number of trigeminal (V) ganglion cells labelled by application of horseradish peroxidase to the vibrissa pad and a 44.8% decrease in the number of Nissl-stained ganglion cells in the ophthalamic-maxillary portion of the V ganglion. These implants also decreased the number of myelinated fibres in the ION. In normal rats killed on P6-10, there was an average of 10273 +/- 1259 myelinated axons in the nerve. In the animals with colchicine- or vinblastine-treated implants, this value was 3891 +/- 1965. The highest axon count in an experimental animal was 9859. In all animals, axoplasmic transport attenuation resulted in the disappearance of normal vibrissae-related cytochrome oxidase patterns in the brainstem, thalamus and primary somatosensory cortex. Axoplasmic transport attenuation did not result in the disappearance of vibrissae-related ordering of V primary afferent terminal arbors, as demonstrated by anterograde labelling with neurobiotin. These results suggest that some factor conveyed from the periphery of the V ganglion and perhaps on to the brainstem is necessary for the maintenance of vibrissae-related patterns in the thalamus and cortex.

Publication types

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

MeSH terms

  • Afferent Pathways / drug effects
  • Animals
  • Animals, Newborn
  • Axonal Transport / drug effects*
  • Brain Stem / drug effects*
  • Brain Stem / metabolism
  • Cerebral Cortex / drug effects*
  • Cerebral Cortex / metabolism
  • Colchicine / pharmacology
  • Ganglia, Sensory / drug effects
  • Nerve Endings / drug effects
  • Nerve Fibers, Myelinated / drug effects
  • Orbit / innervation*
  • Rats
  • Rats, Sprague-Dawley
  • Thalamus / drug effects*
  • Thalamus / metabolism
  • Vibrissae / physiology*
  • Vinblastine / pharmacology

Substances

  • Vinblastine
  • Colchicine