Caffeine dopamine

Caffeine binds to adenosine receptors in the brain, preventing adenosine from inducing sleep or opening blood vessels. Caffeine also increases levels of dopamine, the neurotransmitter associated with pleasure. This is the chemical mechanism for addiction. The response to adenosine competition causes increased adrenaline flow. 

The various stimulants have no obvious chemical relationships and do not share primary neurochemical effects, despite their similar behavioral effects. Cocaines chemical strucmre does not resemble that of caffeine, nicotine, or amphetamine. Cocaine binds to the dopamine reuptake transporter in the central nervous system, effectively inhibiting dopamine reuptake. It has similar effects on the transporters that mediate norepinephrine and serotonin reuptake. As discussed later in this chapter in the section on neurochemical actions mediating stimulant reward, dopamine is very important in the reward system of the brain the increase of dopamine associated with use of cocaine probably accounts for the high dependence potential of the drug. 

Caffeine and nicotine have more complex reinforcing effects on dopamine. Caffeine, a methylxanthine compound, appears to exert its central ac-... 

Garrett BE, Griffiths RR The role of dopamine in the behavioral effects of caffeine in animals and humans. Pharmacol Biochem Behav 57 533—541, 1997... 

The main mechanism of action of caffeine occurs via the blockade of adenosine receptors in the CNS. Adenosine is an autacoid, which is involved in the modulation of behavior, oxygenation of cells, and dilatation of cerebral and coronary blood vessels and indirectly inhibits the release of dopamine. The blockade of adenosine receptors by caffeine increases the activity of dopamine, which is implicated in the effects of caffeine (91). The question that arises from this observation is to know whether or not adenosine antagonists hold potential for the treatment of Parkinsonism, and further study on the adenosine receptor antagonists from medicinal plants should be encouraged. A possible source for such agents could be the medicinal flora of Asia and the Pacific, among which is the family Sapindaceae. 

Caffeine increases extracellular serotonin levels in the hippocampus (Okada et al. 1999). Enhanced release of dopamine and norepinephrine occurs at higher doses (Morgan and Vestal 1989). An inhibition of monoamine reuptake occurs, but only in the millimolar range, which would not matter at normal oral doses (Reith et al. 1987). 

Ethanol, nicotine, caffeine, and phencyclidine stimulate both locomotor activity and dopamine turnover (Wise 1987). Sex differences in DA outflow in the NAC has been shown in response to ethanol. Female rats have a greater ethanol-induced DA outflow, as measured by microdialysis in the NAC, than males and this sexually dimorphic response is regionally specific as it is not observed in the striatum additionally, females consume more alcohol (Blanchard et al. 1993). 

The plasma concentrations of caffeine in the rats exposed to the 0.25 and 1.0 mg ml solutions were within the range of those fonnd in typical users of caffeinated beverages. Caffeine may weakly stimnlate dopamine mechanisms via its antagonist action at adenosine receptors (Herrera-Marschitz et al. 1988 Casas et al. 1989 Ferre et al. 1992 Fredholm et al. 1999), and in small doses it may have enhanced the dopaminergic component in the nicotine discriminative stimulns through an effect... 

Herrera-Marschitz M, Casas M, Ungerstedt U (1988) Caffeine produces contralateral rotation in rats with unilateral dopamine denervation comparisons with apomorphine-induced responses. Psychopharmacology 94 38 5... 

Dopamine Captopril Caffeine Doxycycline Clonazepam Phenobarbital... 

Levodopa or dopamine agonists produce diverse dyskinesias as a dose-related phenomenon in patients with Parkinson s disease dose reduction reverses them. Chorea may also develop in patients receiving phenytoin, carbamazepine, amphetamines, lithium, and oral contraceptives, and it resolves with discontinuance of the offending medication. Dystonia has resulted from administration of dopaminergic agents, lithium, serotonin reuptake inhibitors, carbamazepine, and metoclopramide and postural tremor from theophylline, caffeine, lithium, valproic acid, thyroid hormone, tricyclic antidepressants, and isoproterenol. 

Quarta D, Ferrd S, Solinas M et al (2004) Opposite modulatory roles for adenosine Ai and A2A receptors on glutamate and dopamine release in the shell of the nucleus accumbens. Effects of chronic caffeine exposure. J Neurochem 88 1151-8 Queiroz G, Gebicke-Haerter PJ, Schobert A et al (1997) Release of ATP from cultured rat astrocytes elicited by glutamate receptor activation. Neuroscience 78 1203-8 Queiroz G, Diniz C, Go natives J (2002) Facilitation of noradrenaline release by adenosine A2A receptors in the epididymal portion and adenosine A2B receptors in the prostatic portion of the rat vas deferens. Eur J Pharmacol 448 45-50... 

Acquas E, Tanda G, Di Chiara G (2002) Differential effects of caffeine on dopamine and acetylcholine transmission in brain areas of drug-naive and caffeine-pretreated rats. Neuropsychopharmacology 27 182-193. 

Caffeine 2. Chaste tree 3. Green tea 4. Plantain 1. Lithium 2. Phenothiazines (e.g. chlorpromazine, promazine, levomepromazine, pericyazine, pipotiazine, fluphenazine, perphenazine, trifluphenazine) 3. Clozapine L blood lithium levels with 1 clinical effects. 1 effects of phenothiazines Unknown mechanism (caffeine) Contains dopamine agonists (chaste tree) Induction of metabolizing enzymes (green tea may induce CYP1A2, which metabolizes clozapine) l absorption from the gut (plantain may l absorption of lithium) Be aware. Caffeine withdrawal may precipitate lithium toxicity, so avoid sudden caffeine withdrawal. Avoid concomitant use if possible... 

These studies, and many others, conclude that the acute locomotor stimulant effects of caffeine in animal models are mediated in part by dopaminergic systems and dopamine receptors. Recent studies suggest that tolerance to the locomotor stimulant effects of chronic caffeine may also be related to specific changes in dopaminergic function (128). Thus, in spite of the fact that methylxanthines are structurally different from other psychostimulants, and do not directly affect dopamine transporters or receptors, in fact their stimulant action is derived from effects on central dopamine pathways. 

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