Dopamine reverse

Wickens JR, Begg AJ, Arbuthnott GW (1996) Dopamine reverses the depression of rat cortico-striatal synapses which normally follows high frequency stimulation of cortex in vitro. Neurosci 70 1-5. 

The nigrostriatal system is predominantly involved in motor control, which is particularly evident in Parkinson s disease (PD), where a progressive loss of these neurons results in loss of motor function. In the early stages of the disorder, the motor impairment can be reversed by the administration of the dopamine precursor l-DOPA (L-3,4-dihydroxyphenylalanine), which bypasses the need for TH in dopamine... 

The pharmacology of amphetamine is considerably more complex. It does not only block monoamine reuptake, but also directly inhibits the vesicular monoamine transporter, causing an increase in cytosolic but not vesicular dopamine concentration. This may lead to reverse transport of the amines via the membrane-bound transporters. Further mechanisms of amphetamine action are direct MAO inhibition and indirect release of both dopamine and serotonin in the striatum. 

Example 2-1 The reversible oxidation of dopamine (DA) is a two-electron process. A cyclic voltammetric anodic peak current of 2.2 pA is observed for a... 

Due to its electronic conductivity, polypyrrole can be grown to considerable thickness. It also constitutes, by itself, as a film on platinum or gold, a new type of electrode surface that exhibits catalytic activity in the electrochemical oxidation of ascorbic acid and dopamine in the reversible redox reactions of hydroquinones and the reduction of molecular oxygen iV-substituted pyrroles are excellent... 

ATC A03FA06 A04AD Use anti-emetic, specific antagonist of peripheral and central dopamine receptors, reversible MAO-inhibitor... 

The most consistent and potent antagonism of amphetamine effects on increased motor activity and stereotyped movements is obtained with antagonists at dopamine receptors of the D2 subtype (Creese et al. 1982). This is not the case with amphetamine s disruptive effects on social and aggressive behavior. So far, no antagonists have been identified that reverse amphetamine s disruption of sexual, play, maternal, or aggressive behavior. 

In experiments with mice and squirrel monkeys, we confirmed and extended the antagonism of amphetamine-induced motor hyperactivity by naltrexone at the same time, however, amphetamine s disruption of aggressive and social behavior was not reversed by naltrexone (Winslow and Miczek, in press). Specifically, in mice, the resident s attack and threat behavior toward an intruder was even further reduced by amphetamine after naltrexone pretreatment (figure 7). Squirrel monkeys that are dominant within their social group exhibit significantly lower levels of aggressive display toward other group members and initiate fewer social interactions after amphetamine treatment naltrexone did not block these effects. The interactive effects of amphetamine and naltrexone on locomotor behavior are consistent with the proposed modulation of dopamine-mediated functions by opioids however, the interaction between amphetamine and naltrexone on social behavior appears to involve a different mechanism. 

Imperato, A., and Di Chiara, G. Transtriatal 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 A.966-911, 1984. 

QUESTION How do you imagine that both a receptor antagonist and an uptake inhibitor would block the effects It would seem that if dopamine is involved, it would either be acting on a membrane receptor or inside, but not both. I would also like to ask a more specific question. You showed that the alpha MT protected effect could be reversed by dopa. And I think you imagined that that was because of dopamine formation. But have you tried dopamine agonists to see if they would antagonize either the protective effect of alpha methyltyrosine or, particularly, the protective effect of the dopamine antagonists to try to verily that those protective effects really have to do with blockade of a dopamine receptor as opposed to some other possibility ... 

Rimonabant (382) has also shown promise in pre-clinical and clinical studies as an aid to smoking cessation. (382) decreases nicotine self-administration in rats and nicotine-induced dopamine release in nucleus acumbens [372], and also reversed nicotine-seeking behaviour in rats several weeks... 

After birth, a rapid drop in progesterone level initially triggers lactation through reversal of inhibitory effects on prolactin (Fig. 44-2). Nipple stimulation then enables lactation to continue once established. During lactation, ineffective removal of milk from the breast, trauma, and skin breaks may lead to problems such as milk stasis, nipple pain, and mastitis.12 Additionally, some women have difficultly initiating lactation due to improper technique and/or activity of inhibitors such as dopamine (Fig. 44-2). 

Cory-Slechta DA, McKoy L, Richfield EK. 1997c. Time course and regional basis of Pb-induced changes in MK-801 binding Reversal by chronic treatment with the dopamine agonist apomorphine but not the D1 agonist SKF-82958. J Neurochem 68 2012-2023. 

A poly(aniline boronic acid)-based conductimetric sensor for dopamine consisting of an interdigitated microarray electrode coated with poly(aniline boronic acid) has also been developed by the Fabre team. The sensor was found to show a reversible chemoresistive response to dopamine without interference by ascorbic acid from their mixtures.42... 

Jacocks, H.M. and Cox, B.K., Serotonin-stimulated [3H]dopamine via reversal of the dopamine transporter in rat striatum and nucleus accumbens a comparison with release elicited by potassium, N-methyl-D-aspartic acid, glutamic acid and D-amphetamine, J. Pharmacol. Exp. Ther., 262, 356, 1992. 

Sulzer, D., Maidment, N.T., and Rayport, S., Amphetamine and other weak bases act to promote reverse transport of dopamine in ventral midbrain neurons, J. Neurochem., 60, 527, 1993. 

Kokoshka, J.M., Vaughan, R.A., Hanson, G.R., Fleckenstein, A.E. Nature of methamphetamine-induced rapid and reversible changes in dopamine transporters. Eur. J. Pharmacol. 361 269, 1998. 

The first two antidepressants, iproniazid and imipramine, were developed in the same decade. They were shown to reverse the behavioural and neurochemical effects of reserpine in laboratory rodents, by inhibiting the inactivation of these monoamine transmitters (Leonard, 1985). Iproniazid inhibits MAO (monoamine oxidase), an enzyme located in the presynaptic neuronal terminal which breaks down NA, 5-HT and dopamine into physiologically inactive metabolites. Imipramine inhibits the reuptake of NA and 5-HT from the synaptic cleft by their transporters. Therefore, both of these drugs increase the availability of NA and 5-HT for binding to postsynaptic receptors and, therefore, result in enhanced synaptic transmission. Conversely, lithium, the oldest but still most frequently used mood stabiliser (see below), decreases synaptic NA (and possibly 5-HT) activity, by stimulating their reuptake and reducing the availability of precursor chemicals required in the biosynthesis of second messengers. 

The first CNT-modified electrode was reported by Britto et al. in 1996 to study the oxidation of dopamine [16]. The CNT-composite electrode was constructed with bro-moform as the binder. The cyclic voltammetry showed a high degree of reversibility in the redox reaction of dopamine (see Fig. 15.3). Valentini and Rubianes have reported another type of CNT paste electrode by mixing CNTs with mineral oil. This kind of electrode shows excellent electrocatalytic activity toward many materials such as dopamine, ascorbic acid, uric acid, 3,4-dihydroxyphenylacetic acid [39], hydrogen peroxide, and NADH [7], Wang and Musameh have fabricated the CNT/Teflon composite electrodes with attractive electrochemical performance, based on the dispersion of CNTs within a Teflon binder. It has been demonstrated that the electrocatalytic properties of CNTs are not impaired by their association with the Teflon binder [15]. 

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