Opioid-Mediated Modulation of Calcium Currents in Striatal and Pallidal Neurons Following Reserpine Treatment: Focus on Kappa Response

Francesca Spadoni, Giuseppina Martella, Alessandro Martorana, Franco Lavaroni, Vincenza D'Angelo, Giorgio Bernardi, Alessandro Stefani

Research output: Contribution to journalArticle

Abstract

Previous work has shown that enkephalins target N-type calcium (Ca 2+) channels in striatal and globus pallidus (GP) neurons, principally through activation of μ-like receptors. Here, we examined the effects of selective μ, γ, and κ agonists on Ca2+ currents in striatal and GP neurons isolated from either control or reserpine-treated rats. In cells from control rats DAMGO and dynorphin (DYN) inhibited high-voltage-activated (HVA) Ca2+ currents preferentially in "medium-to-small" GP cells (likely to correspond to parvalbumin-negative cells). The κ response was elicited by several agonists (DYN 17, DYN 13, BRL, U50-488-H), U50-488-H being the most effective (>30% maximal inhibition). U50-488-H affected both ω -CgTxGVIA-sensitive and nimodipine-sensitive Ca2+ conductances. The κ-mediated effect (but not the μ response) was slow and blocked by chelerythrine, supporting the involvement of protein kinase C. In neurons from reserpinized rats we observed modest changes in the μ-inhibited fraction in small GP cells and a dramatic reduction of the κ-sensitive fraction in principal striatal cells. These data imply that aminergic depletion alters opiate transmission differentially in the indirect and direct pathways. The suppression of the κ response only in striatum reinforces the notion of an imbalance of endogenous opiates as relevant in extrapyramidal motor dysfunctions.

Original languageEnglish
Pages (from-to)194-205
Number of pages12
JournalSynapse
Volume51
Issue number3
DOIs
Publication statusPublished - Mar 1 2004

Keywords

  • μ, κ opioid agonists
  • Basal ganglia
  • Dopamine depletion
  • PKC

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)
  • Pharmacology

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    Spadoni, F., Martella, G., Martorana, A., Lavaroni, F., D'Angelo, V., Bernardi, G., & Stefani, A. (2004). Opioid-Mediated Modulation of Calcium Currents in Striatal and Pallidal Neurons Following Reserpine Treatment: Focus on Kappa Response. Synapse, 51(3), 194-205. https://doi.org/10.1002/syn.10294