On the potassium conductance increased by opioids in rat locus coeruleus neurones.

R. A. North, John Williams

Research output: Contribution to journalArticle

198 Citations (Scopus)

Abstract

Intracellular recordings were made from locus coeruleus neurones in slices cut from rat pons and superfused in vitro. Membrane currents were recorded with a single‐electrode switch‐clamp amplifier. Opioids, enkephalin analogues or morphine, caused a concentration‐dependent potassium current, which had a maximum value of about 300 pA at ‐60 mV. The opioid‐sensitive potassium conductance was independent of membrane potential between ‐60 and ‐130 mV, but became less as the membrane potential was changed from ‐60 to ‐30 mV. The opioid outward current was reduced by quinine (100 microM‐1 mM) and barium (30 microM‐2 mM), but not by 4‐aminopyridine (100 microM‐1 mM) or tetraethylammonium (10 mM). A potassium current with similar properties flowed for several seconds after a burst of action potentials; this appeared to result from calcium entering the neurone during the action potentials. The alpha 2‐adrenoceptor agonists noradrenaline and clonidine caused a concentration‐dependent potassium conductance increase which had the same maximum value as that caused by opioids in the same neurones. Experiments in which an opioid and an alpha 2‐adrenoceptor agonist were superfused together indicated that the same potassium conductance is increased by both agonists.

Original languageEnglish (US)
Pages (from-to)265-280
Number of pages16
JournalJournal of Physiology
Volume364
Issue number1
DOIs
StatePublished - Jul 1 1985
Externally publishedYes

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Locus Coeruleus
Opioid Analgesics
Potassium
Neurons
Membrane Potentials
Action Potentials
Tetraethylammonium
Quinine
Pons
Enkephalins
Clonidine
Barium
Morphine
Norepinephrine
Calcium
Membranes

ASJC Scopus subject areas

  • Physiology

Cite this

On the potassium conductance increased by opioids in rat locus coeruleus neurones. / North, R. A.; Williams, John.

In: Journal of Physiology, Vol. 364, No. 1, 01.07.1985, p. 265-280.

Research output: Contribution to journalArticle

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