Article date: September 1972
By: BERNARD J. CARROLL, PETER T. SHARP in Volume 46, Issue 1, pages 124-139
. The dose‐response relationship for hyperactivity in grouped mice following the injection of morphine sulphate has been established.
. The activation response can be modified by drugs which affect either catecholamines or indoleamines.
. The monoamine precursors l‐DOPA and 5‐hydroxytryptophan potentiate the response.
. The monoamine synthesis inhibitors α‐methyl‐p‐tyrosine and p‐chlorophenylalanine reduce the response.
. Inhibition of monoamine oxidase activity by pargyline caused a great increase in the response. The simultaneous administration of reserpine resulted in a further potentiation.
. Reserpine blocked the response whenever it was given alone, either before, with or after the injection of morphine.
. Blockade of α‐adrenoceptors with phentolamine or phenoxybenzamine reduced the response.
. Blockade of tryptaminergic receptors with methysergide or cinanserin also antagonized the response.
. The major tranquillizers haloperidol and chlorpromazine reduced the response. Haloperidol was especially effective in this regard.
. The tricyclic antidepressant drug imipramine potentiated the response.
. The morphine antagonist nalorphine completely prevented the response.
. The anticholinergic agent atropine and the antihistaminic drug mepyramine did not affect the response.
. We conclude that dopamine, noradrenaline and 5‐hydroxytryptamine are all involved in the normal activation response of grouped mice to morphine, with dopaminergic mechanisms being of primary importance.
. The dose‐response relationship for hyperactivity in grouped mice following the injection of morphine sulphate has been established.
. The activation response can be modified by drugs which affect either catecholamines or indoleamines.
. The monoamine precursors l‐DOPA and 5‐hydroxytryptophan potentiate the response.
. The monoamine synthesis inhibitors α‐methyl‐p‐tyrosine and p‐chlorophenylalanine reduce the response.
. Inhibition of monoamine oxidase activity by pargyline caused a great increase in the response. The simultaneous administration of reserpine resulted in a further potentiation.
. Reserpine blocked the response whenever it was given alone, either before, with or after the injection of morphine.
. Blockade of α‐adrenoceptors with phentolamine or phenoxybenzamine reduced the response.
. Blockade of tryptaminergic receptors with methysergide or cinanserin also antagonized the response.
. The major tranquillizers haloperidol and chlorpromazine reduced the response. Haloperidol was especially effective in this regard.
. The tricyclic antidepressant drug imipramine potentiated the response.
. The morphine antagonist nalorphine completely prevented the response.
. The anticholinergic agent atropine and the antihistaminic drug mepyramine did not affect the response.
. We conclude that dopamine, noradrenaline and 5‐hydroxytryptamine are all involved in the normal activation response of grouped mice to morphine, with dopaminergic mechanisms being of primary importance.
DOI: 10.1111/j.1476-5381.1972.tb06855.x
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