Summary
The novel technique of microdialysis has been used to examine the basal and K+-induced release of catecholamines and metabolites from the anterior hypothalamus of the urethane-anaesthetized rat in vivo. A high pressure liquid chromatographic assay was developed to simultaneously measure endogenous noradrenaline, dopamine and their intraneuronal metabolites 3,4-dihydroxyphenylglycol (DOPEG) and 3,4-dihydroxyphenylacetic acid (DOPAC) respectively, in each 60 μl dialysate sample. The effect of replacing Ca2+ in the perfusion fluid with a low concentration of Cd2+, which blocks Ca2+ effects, was also studied. Increasing the K+ concentration in the perfusion fluid elicited a concentration-dependent increase in noradrenaline and dopamine release. In contrast, there were marked reductions in DOPEG and DOPAC which were not concentration-dependent. In the Ca2+-depleted conditions, the K+-induced increase in amine release was significantly attenuated, but the reductions in the metabolites were not affected. We suggest that the mechanisms contributing to the observed reductions in the metabolites may be inhibition of neuronal reuptake, an increase in neuronal efflux, an enhancement of vesicular uptake and a decrease in vesicular efflux.
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References
Adams P (1982) Voltage-dependent conductances of vertebrate neurones. TINS 5:116–119
Colburn RW, Goodwin FK, Murphy DL, Bunney WE Jr, Davis JM (1968) Quantitative studies of norepinephrine uptake by synaptosomes. Biochem Pharmacol 17:957–964
Dennis T, L'Heureux R, Carter C, Scatton B (1987) Presynaptic alpha-2 adrenoceptors play a major role in the effects of idazoxan on cortical noradrenaline release (as measured by in vivo dialysis) in the rat. J Pharmacol Exp Ther 241:642–649
Eriksson B-M, Persson B-A (1982) Determination of catecholamines in the rat heart tissue and plasma by liquid chromatography with electrochemical detection. J Chromatography 228:143–154
Farah MB, Adler-Graschinsky E, Langer SZ (1977) Possible physiological significance of the initial step in the catabolism of noradrenaline in the central nervous system of the rat. Naunyn-Schmiedeberg's Arch Pharmacol 297:119–131
Garcia AG, Kirpekar SM (1973) Release of noradrenaline from the cat spleen by sodium deprivation. Br J Pharmacol 47:729–747
Glowinski J, Iversen LL (1966) Regional studies of catecholamines in the rat brain — I The disposition of 3H norepinephrine, 3H dopamine and 3H DOPA in various regions of the rat brain. J Neurochem 13:655–669
Gonon F, Buda M, De-Simoni G, Pujol JF (1983) Catecholamine metabolism in the rat locus coeruleus as studied by in vivo differential pulse voltametry. II. Pharmacological and behavioural study. Brain Res 273:207–216
Holz RW, Coyle JT (1974) The effects of various salts, temperature, and the alkaloids veratridine and batrachotoxin on the uptake of (3H) Dopamine into synaptosomes from rat striatum. Mol Pharmacol 10:746–758
Imperato A, Di Chiara G (1984) Trans-striatal dialysis coupled to reverse phase high performance liquid chromatography with electrochemical detection: A new method for the study of the in vivo release of endogenous dopamine and metabolites. J Neurosci 4:966–977
Kapoor V, Chalmers JP (1987) A simple, sensitive method for the determination of extracellular catecholamines in the rat hypothalamus using in vivo dialysis. J Neurosci Meth 19:173–182
Lagnado JR, Sourkes TL (1956) Inhibition of amine oxidase by metal ions and by sulphydryl compounds. Can J Biochem Physiol 34:1185–1194
L'Heureux R, Dennis T, Curet O, Scatton B (1986) Measurement of endogenous noradrenaline release in the rat cerebral cortex in vivo by transcortical dialysis: Effects of drugs affecting noradrenergic transmission. J Neurochem 46:1794–1801
Majewski H, Hedler L, Steppeler A, Starke K (1982) Metabolism of endogenous and exogenous noradrenaline in the rabbit perfused heart. Naunyn-Schmiedeberg's Arch Pharmacol 319:125–129
Parker EM, Cubeddu LX (1985) Evidence for autoreceptor modulation of endogenous dopamine release from rabbit caudate nucleus in vitro. J Pharmacol Exp Ther 232:492–500
Paton DM (1973) Mechanism of efflux of noradrenaline from adrenergic nerves in rabbit atria. Br J Pharmacol 49:614–627
Raiteri M, Cerrito F, Cervoni AM, Levi G (1979) Dopamine can be released by two mechanisms differentially affected by the dopamine transport inhibitor nomifensine. J Pharmacol Exp Ther 208:195–202
Routledge C, Marsden CA (1987) Electrical stimulation of the C1 region of the rostral ventrolateral medulla of the rat increases mean arterial pressure and adrenaline release in the posterior hypothalamus. Neuroscience 20:457–466
Stute N, Trendelenburg U (1984) The outward transport of axoplasmic noradrenaline induced by a rise of the sodium concentration in the adrenergic nerve endings of the rat vas deferens. Naunyn-Schmiedeberg's Arch Pharmacol 327:124–132
Taube HD, Starke K, Borowski E (1977) Presynaptic receptor systems on the noradrenergic neurones of rat brain. Naunyn-Schmiedeberg's Arch Pharmacol 299:123–141
Thiede HM, Kehr W (1981) Catecholamine metabolism in rat brain. The role of neutral and acidic catechol metabolites. Naunyn-Schmiedeberg's Arch Pharmacol 318:29–35
Trendelenburg U (1986) The metabolizing systems involved in the inactivation of catecholamines. Naunyn-Schmiedeberg's Arch Pharmacol 332: 201–207
Tyce GM, Rorie K (1985) Effects of l-dopa and l-tyrosine on release of free and conjugated dopamine, homovanillic acid and dihydroxyphenylacetic acid from slices of rat striatum. Life Sci 37:2439–2448
Ungell A-L, Graefe K-H (1987) Failure of K+ to affect the potency of inhibitors of the neuronal noradrenalinbe carrier in the rat vas deferens. Naunyn-Schmiedeberg's Arch Pharmacol 335: 250–254
Ungerstedt U (1984) Measurement of neurotransmitter release by intracranial dialysis. In: Marsden CA (ed) Measurement of neurotransmitter release in vivo. John Wiley and Sons Ltd, Chichester, pp 81–105
Westerink BHC, Damsma G, Rollema H, De Vries JB, Horn AS (1987) Scope and limitations of in vivo brain dialysis: A comparison of its application to various neurotransmitter systems. Life Sci 41:1763–1776
Zetterström T, Sharp T, Collin AK, Ungerstedt U (1988) In vivo measurement of extracellular dopamine and DOPAC in rat striatum after various dopamine-releasing drugs; Implications for the origin of extracellular DOPAC. Eur J Pharmacol 148:327–334
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Badoer, E., Würth, H., Türek, D. et al. The K+-induced increases in noradrenaline and dopamine release are accompanied by reductions in the release of their intraneuronal metabolites from the rat anterior hypothalamus. Naunyn-Schmiedeberg's Arch Pharmacol 339, 54–59 (1989). https://doi.org/10.1007/BF00165126
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DOI: https://doi.org/10.1007/BF00165126