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THE ACTION OF MICROELECTROPHORETICALLY APPLIED (3,4‐DIHYDROXY‐PHENYLAMINO)‐2‐IMIDAZOLINE (DPI) ON SINGLE CORTICAL NEURONES
Author(s) -
BEVAN P.,
BRADSHAW C.M.,
PUN R.Y.K.,
SLATER N.T.,
SZABADI E.
Publication year - 1979
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1979.tb07884.x
Subject(s) - excitatory postsynaptic potential , dopamine , acetylcholine , chemistry , phenylephrine , imidazoline receptor , pharmacology , endocrinology , medicine , inhibitory postsynaptic potential , blood pressure
1 The technique of microelectrophoresis was used in order to compare the actions of the imidazoline derivative, (3,4‐dihydroxy‐phenylamino)‐2‐imidazoline (DPI), with those of dopamine and phenylephrine on single neurones in the cerebral cortex of the rat anaesthetized with halothane. 2 DPI and phenylephrine were almost exclusively excitatory, whereas dopamine could evoke both excitatory and depressant responses. 3 In the case of excitatory responses, DPI appeared to be more potent than dopamine, and was approximately equipotent with phenylephrine. 4 The dopamine antagonist, haloperidol, could discriminate between excitatory responses to DPI and dopamine: responses to dopamine were abolished, whereas responses to DPI, and to a control agonist, acetylcholine, were unaffected. 5 The α‐adrenoceptor antagonist, phenoxybenzamine, antagonized equally excitatory responses to DPI and phenylephrine. Responses to acetylcholine were not affected. 6 It is concluded that DPI does not stimulate dopamine receptors on cortical neurones; the excitatory responses of these cells to DPI may be mediated by α‐adrenoceptors.