Catecholamine inhibition of calcium action potentials in rat locus coeruleus neurones

John Williams, R. A. North

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Intracellular recordings were made from neurones in the nucleus locus coeruleus in a slice of tissue cut from the rat pons. Clonidine (100nM-10μM), noradrenaline (10μM-1 mM) and adrenaline (10μM-1 mM) all reduced the duration of the spontaneously occurring action potential of the neurones. This effect was also observed on the action potential in the presence of tetrodotoxin, which results from calcium entering the cell. These concentrations of clonidine, noradrenaline and adrenaline always hyperpolarized the membrane. This hyperpolarization was prevented by two procedures which block potassium currents-intracellular caesium and extracellular barium. In conditions of potassium current blockade, noradrenaline (100 μM-1 mM) and adrenaline (20μM-1 mM) shortened the calcium action potential but clonidine was ineffective even at 10 μM. Adrenaline and noradrenaline also suppressed inward calcium and barium currents measured under voltage clamp. This action of noradrenaline and adrenaline was not prevented by yohimbine (10 μM), propranolol (20 μM) or prazosin (1 μM); it was reduced by a concentration of phentolamine about 100 times higher than its Ke for α2-adrenoceptors on locus coeruleus neurones. It is concluded that noradrenaline and adrenaline can directly inhibit calcium action potentials in locus coeruleus neurones when applied in high concentrations, but that this does not involve an α2-adrenoceptor.

Original languageEnglish (US)
Pages (from-to)103-109
Number of pages7
JournalNeuroscience
Volume14
Issue number1
DOIs
StatePublished - 1985
Externally publishedYes

Fingerprint

Locus Coeruleus
Epinephrine
Action Potentials
Catecholamines
Norepinephrine
Calcium
Neurons
Clonidine
Barium
Adrenergic Receptors
Potassium
Cesium
Yohimbine
Pons
Prazosin
Phentolamine
Tetrodotoxin
Propranolol
Membranes

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Catecholamine inhibition of calcium action potentials in rat locus coeruleus neurones. / Williams, John; North, R. A.

In: Neuroscience, Vol. 14, No. 1, 1985, p. 103-109.

Research output: Contribution to journalArticle

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