Apomorphine inhibition

Ellinwood, E.H., Jr., and Lee, T. Effect of continuous systemic infusion of d-amphetamine on the sensitivity of nigral dopamine cells to apomorphine inhibition of firing rates. Brain Res 273 379-383, 1983. 

When tested on prolactin release in isolated mammatrophs of bovine anterior pituitary, apomorphine appeared a full agonist (inhibiting release) while antagonism of the inhibition of prolactin release by the neuroleptics showed a potency more similar to that for binding than for blocking cAMP production. Also the inhibition of prolactin... 

In other brain areas which receive a DA input, such as the nucleus accumbens and prefrontal cortex, it appears to be inhibitory and predominently D2-mediated. This is clear from Fig. 7.5 which shows inhibition by apomorphine (mixed D2, Di agonists) of the firing of neurons in the medial prefrontal cortex of the anaesthetised rat and its antagonism by the D2 antagonist haloperidol. 

The biplots show which binding tests are predictive for which pharmacological tests. Binding to the haloperidol and apomorphine labeled receptors corresponds with inhibition of agitation and stereotypy in rats, binding to the spiperone receptor... 

Metoclopramide, administered at doses higher than those required to inhibit apomorphine-induced emesis, was more effective than haloperidol in antagonizing cisplatin-induced emesis in dogs [80]. This was observed despite the fact that metoclopramide was considerably weaker than haloperidol as a D2-dopamine antagonist [43]. Subsequently, antiemetic efficacy of metoclopramide administered at high doses has been reported in cancer patients... 

Inhibition of conditioned (but not unconditioned) avoidance behavior is one of the most predictive tests of antipsychotic action. Another is the inhibition of amphetamine- or apomorphine-induced stereotyped behavior. Other tests that may predict antipsychotic action are reduction of exploratory behavior without undue sedation, induction of a cataleptic state, inhibition of intracranial self-stimulation of reward areas, and prevention of apomorphine-induced vomiting. Most of these tests are difficult to relate to any model of clinical psychosis. 

Spinal KAtp channels were shown to be involved in the antinociception produced by intrathecally (i.t.) administered morphine, norepinephrine, apomorphine and carbachol as deduced from the dose-dependent inhibition by i.t. glibenclamide. 

Kohn, H.I. and Liversedge, M. 1944. On a new aerobic metabolite whose production by brain is inhibited by apomorphine, emetine, ergotamine, epinephrine, and menadione. J. Pharmacol. Exp. Ther. 82 292-300. 

Stoof JC, De Boer T, Sminia P, Mulder AH (1982) Stimulation of D2-dopamine receptors in rat neostriatum inhibits the release of acetylcholine and dopamine but does not affect the release of gamma-aminobutyric acid, glutamate or serotonin. Eur J Pharmacol 84 211-14 Subramony JA (2006) Apomorphine in dopaminergic therapy. Mol Pharmaceut 3 380-5 Takeshita Y, Watanabe T, Sakata T, Munakata M, Ishibashi H, Akaike N (1998) Histamine modulates high-voltage-activated calcium channels in neurons dissociated from the rat tuberomam-millary nucleus. Neuroscience 87 797-805... 

For each response examined, inhibition of isoproterenol-stimulated cAMP accumulation by intact cells ( ) inhibition of basal release of IR-aMSH by intact cells ( J occupancy of specific [3H]-spiroperidol binding sites in a cell-free homogenate (Q) and inhibition of isoproterenol-stimulated adenylate cyclase activity in a cell-free homogenate (M), the effect achieved with the indicated concentration of apomorphine is expressed as a percentage of the maximal effect of apomorphine (33). 

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