Calcium influx in rat thalamic relay neurons through voltage-dependent calcium channels is inhibited by enkephalin

Alessandro Formenti, Elda Arrigoni, Marzia Martina, Stefano Taverna, Giuliano Avanzini, Mauro Mancia

Research output: Contribution to journalArticle

Abstract

High and low voltage-activated, transient (HVA and LVA,T) Ca2+ currents are crucial in determining the characteristic thalamic firing pattern, during the oscillatory mode. The modulatory effects induced by d-ala2-d-leu5-enkephalin (DADLE) on voltage-dependent Ca2+ channels have been investigated on acutely dissociated neurons from rat ventro-basal (VB) thalamus, by means of whole cell patch-clamp technique. DADLE (400 nM) reduced HVA Cat+ channel currents in 37 out of 44 cells tested (-53 ± 5.3% to 0 mV test potential, n = 24,). In 50% of the cases DADLE induced an effect which was persistent at all the potentials tested, i.e. a voltage-independent one. In the remaining neurons, the inhibition partially or totally disappeared on the currents evoked at the highest potentials. DADLE was also able to inhibit LVA Ca2+ channels (-40% in five out of 12 cells). In conclusion, thalamic relay neurons present opioid receptors negatively coupled to both HVA and LVA Ca2+ channels. The presence of two inhibitory effects of DADLE on the total HVA Ca2+ channels has been observed, and they are distinguishable on the basis of their sensitivity to voltage. It is suggested that Ca2+ current modulation may play a role in the production and tuning of the rhythmic burst discharge in these neurons.

Original languageEnglish
Pages (from-to)21-24
Number of pages4
JournalNeuroscience Letters
Volume201
Issue number1
DOIs
Publication statusPublished - Dec 1 1995

Keywords

  • Calcium-current modulation
  • Enkephalin
  • Opioid
  • Rat
  • Rhythmic burst discharge
  • Thalamus
  • Ventro-basal complex

ASJC Scopus subject areas

  • Neuroscience(all)

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