Tyrosine kinase B and C receptors in the neostriatum and nucleus accumbens are co-localized in enkephalin-positive and enkephalin-negative neuronal profiles and their expression is influenced by cocaine

Neuroscience. 2003;117(1):147-56. doi: 10.1016/s0306-4522(02)00802-3.

Abstract

Single- and double-label immunohistochemistry were used to determine the extent to which the tyrosine kinase B and C receptors, are expressed in enkephalin-immunopositive or enkephalin-immunonegative neuronal profiles in the rat neostriatum and nucleus accumbens. Results indicate that tyrosine kinase B and C receptors are co-localized in both enkephalin-positive and enkephalin-negative neurons in both of these nuclei, which suggests that these receptors influence both the striatal-pallidal (enkephalin) and striatal-ventral mesencephalic (substance P/dynorphin) pathways. We also examined the influence of acute or repeated injections of cocaine on the number of tyrosine kinase B and C receptors immunoreactive neuronal profiles in the rat neostriatum and nucleus accumbens. Following an acute injection of cocaine (15 mg/kg, i.p.), there were significant decreases in the number of tyrosine kinase B and C receptors immunoreactive profiles in specific regions of the neostriatum and nucleus accumbens relative to saline-pretreated rats. One or 14 days following the last of seven daily injections of 15 mg/kg cocaine or saline there were no differences in the numbers of tyrosine kinase B or C receptors immunoreactive neuronal profiles between these treatment groups.Collectively, the present results indicate that tyrosine kinase B and C receptors in the neostriatum and nucleus accumbens are co-localized in enkephalin-positive and enkephalin-negative neuronal profiles, which suggests that the striatal medium spiny neurons expressing tyrosine kinase B and C receptors include those that project to the pallidum or the ventral mesencephalon. The current results also show that an acute injection of cocaine results in a decrease in the number of tyrosine kinase B and C receptors immunoreactive neuronal profiles in specific regions of the nucleus accumbens and neostriatum, indicating that cocaine-induced increases in extracellular dopamine in the striatal complex result in compensatory decreases in the expression of tyrosine kinase B and C receptors.

Publication types

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

MeSH terms

  • Animals
  • Cocaine / pharmacology*
  • Enkephalins / analysis
  • Enkephalins / biosynthesis*
  • Gene Expression Regulation / drug effects
  • Gene Expression Regulation / physiology
  • Male
  • Neostriatum / chemistry*
  • Neostriatum / drug effects
  • Neostriatum / metabolism
  • Neurons / chemistry
  • Neurons / drug effects
  • Neurons / metabolism
  • Nucleus Accumbens / chemistry*
  • Nucleus Accumbens / drug effects
  • Nucleus Accumbens / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, trkB / analysis*
  • Receptor, trkB / biosynthesis
  • Receptor, trkC / analysis*
  • Receptor, trkC / biosynthesis

Substances

  • Enkephalins
  • Receptor, trkB
  • Receptor, trkC
  • Cocaine