Interactions Between Cocaine, Tyramine and Noradrenaline at the Noradrenaline Store

Farrant, J. Mark

doi:10.1111/j.1476-5381.1963.tb01491.x

Cited by 7 publications

(4 citation statements)

References 15 publications

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“…It is well known that desipramine inhibits the indirect sympathomimetic effect of tyramine (Farrant, 1963;Furchgott, Kirpekar, Rieker & Schwab, 1963) by competing with tyramine for a common amine pump (Trendelenburg, 1961;Farmer & Petch, 1963). In the present study, desipramine failed to inhibit the effects of ethacrynic acid.…”

Section: Discussioncontrasting

confidence: 39%

Tachyphylaxis to Ethacrynic Acid in the Isolated Atrium of Guinea‐pig and Its Relation to Noradrenaline Stores

Khoyi¹,

Pousti

Powis³

et al. 1978

British J Pharmacology

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The isolated electrically‐paced atrium of the guinea‐pig developed a dose‐dependent increase in the force of contraction in response to ethacrynic acid (12–100 μg/ml) which was blocked by pretreatment of the animals with reserpine but was unaffected by desipramine or colchicine added to the bathing medium. There was a rapidly developing tachyphylaxis to repeated doses of ethacrynic acid which was not reversed by rest or incubation of the tissue with noradrenaline. There was no cross tachyphylaxis between ethacrynic acid and tyramine, amphetamine or nicotine. Ethacrynic acid (200 μg/ml) decreased the noradrenaline content of the atria by 32%. It is concluded that ethacrynic acid exerts its effects indirectly through the release of endogenous noradrenaline and that the mechanism of release seems to be different from that of other known indirect sympathomimetic drugs.

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Section: Discussioncontrasting

confidence: 39%

Tachyphylaxis to Ethacrynic Acid in the Isolated Atrium of Guinea‐pig and Its Relation to Noradrenaline Stores

Khoyi¹,

Pousti

Powis³

et al. 1978

British J Pharmacology

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“…), which competes for the noradrenaline store (Farrant, 1963) and should hinder reabsorption of the amine by the secretory cells, higher values for the amounts of amine secreted were obtained. For instance, in two experiments in which twenty shocks at 1/sec were applied, the mean secretion of 1-96 ng amine/shock rose to 7-8 ng/shock after the cocaine injection.…”

Section: Resultsmentioning

confidence: 96%

Physiology and pharmacology of the splanchnic‐adrenal medullary junction.

Marley¹,

Prout²

1965

The Journal of Physiology

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The adrenal medulla is the ancestral homologue of autonomic ganglia. The innervation of the medulla through a complex of nerves rather than a single trunk allows physiological dissection of synaptic behaviour. In previous experiments, synaptic function within the adrenal medulla of the cat has been studied by testing its response to nervous excitation and by investigating properties such as threshold, fatigue and susceptibility to ganglion-blocking drugs (Marley & Paton, 1961). New data are here presented on the threshold to nerve excitation, spatial and temporal recruitment, fatigue, the effect of drugs on these phenomena and the presence of functional units within the adrenal medulla. The preliminary findings have been communicated to the Physiological Society (Marley, 1961;Marley & Prout, 1963). METHODSCats were anaesthetized with chloralose (80 mg/kg i.v.) after induction with ethyl chloride and ether. The vagi were cut in the neck and the animal was artificially respired. Carotid arterial blood pressure was recorded with a mercury manometer on a kymograph.Usually the splanchnic nerves of one side were stimulated. They were approached retroperitoneally through a lumbar incision and the adrenolumbar vessels were divided between ligatures. As described elsewhere (Marley & Prout, 1965), there are three or four upper splanchnic nerves to the adrenal medulla. These were identified and cut through and the sympathetic chain was removed from the first to the fourth lumbar sympathetic ganglia. The abdominal viscera including the adrenal gland not under test were removed, and the renal vessels were tied. Heparin (10 mg/kg i.v.) was injected. In several recovery experiments the adrenal glands were chronically denervated under aseptic conditions, the cats being anaesthetized with halothane (Fluothane) and oxygen by a modification of the method for anaesthetizing new-born animals (Marley & Payne, 1962). These cats were re-anaesthetized with chloralose 10-14 days later and prepared as described.The splanchnic nerves were stimulated with platinum electrodes (cathode distal) using supramaximal rectangular (0-5 msec) pulses of 20 V at varying frequencies. The excitation frequency and number of stimuli were counted with a Racal digital frequency meter. For rapid excitation with up to ten stimuli, one stimulator provided the excitation frequency and the other a variable 'gate' during which a Stevens-Arnold 'millisec relay' was closed connecting the first stimulator to the electrodes; the stimuli were counted on an oscilloscope. In experiments to determine the stimulation frequency for optimal sympathin output, as well as those in which cocaine or phenoxybenzamine was injected into the cat, the excitation 31-2

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“…By combining these two ideas, one could infer that cocaine probably acts at the neuron membrane a t a common site of entrance or exit of endogenous catecholamines. That cocaine has no depleting action on peripheral catecholamine stores has been demonstrated (5,18).…”

Section: Discussionmentioning

confidence: 97%

“…Methylphenidate increases both pressor and nictitating membrane responses to norepinephrine and epinephrine, while reducing the responses to tyramine and ephedrine (5). Thus, methylphenidate has the ability to potentiate direct acting compounds while antagonizing the action of indirect compounds.…”

Section: Discussionmentioning

confidence: 99%