Behavior, serotonin

Serotonin is a key transmitter in CNS function. Altered serotonergic function has been implicated in many CNS disorders including depression, feeding behavior, sleep disorders, schizophrenia, and Alzheimer s disease. 

Beginning in the 1960s, ben2odia2epiae anxiolytics and hypnotics rapidly became the standard prescription dmg treatment. In the 1980s, buspkone [36505-84-7] (3), which acts as a partial agonist at the serotonin [50-67-9] (5-hydroxytryptamine, 5-HT) type lA receptor, was approved as treatment for generali2ed anxiety. More recently, selective serotonin reuptake inhibitors (SSRIs) have been approved for therapy of panic disorder and obsessive—compulsive behavior. 

Other studies indicate that sucrose does not cause hyperactivity. Carbohydrate ingestion increases levels of serotonin (5-hydroxytryptamine), a brain neurotransmitter that promotes relaxation and sleep. Dietary sucrose should theoretically have a calming effect and reduce activity, manifestations which have been observed in case studies (63). To date, clinical investigations have failed to show a significant connection between sucrose consumption and aggressive or dismptive behavior (66). 

Another theory for the action of stimulant diugs in ADHD involves effects on nonstiiatal monoamine systems. Frontal cortical dopamine, norepinephrine, and serotonin are clearly important in cognitive functioning and impulse control. These neurotransmitters directly modulate reward-related behaviors associated with the striatal dopamine system. Moreover, the amygdala may be pharmacologically influenced leading to enhanced... 

Naranjo CA, Sellers EM, Chater K, et al Non-pharmacological interventions in acute alcohol withdrawal. Clin Pharmacol Ther 34 214—219, 1983 Naranjo CA, Sellers EM, Roach CA, et al Zimelidine-induced variations in alcohol intake hy nondeptessed heavy drinkers. Clin Pharmacol Ther 35 374-381, 1984 Naranjo CA, Sellers EM, Sullivan ]T, et al The serotonin uptake inhibitor citalopram attenuates ethanol intake. Clin Pharmacol Ther 41 266-274, 1987 Naranjo CA, Sullivan ]T, Kadlec KE, et al Differential effects of viqualine on alcohol intake and other consummatory behaviors. Clin Pharmacol Ther 46 301 -309,1989 Naranjo CA, Kadlec KE, Sanhueza P, et al Fluoxetine differentially alters alcohol intake and other consummatory behaviors in problem drinkers. Clin Pharmacol Ther 47 490 98, 1990... 

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. 

Leibowitz, SF, Alexander, JT (1998) Hypothalamic serotonin in control of eating behavior, meal size, and body weight. Biol. Psychiatry 44 851-864. 

Weiss, JM, Goodman, PA, Lostito, BG, Corrigan, S, Charry, JM and Bailey, WH (1981) Behavioral depression produced by an uncontrollable stressor relationship to norepinephrine, dopamine and serotonin levels in various regions of rat brain. Brain Res. Rev. 3 167-205. 

In view of this neurotoxicity, we will review some data relevant to this process. First, we will review data showing that methamphetamine (METH), a prototypic psychomotor stimulant, which has been widely used for nonmedical purposes at doses often a good deal higher than therapeutie doses, is neurotoxic to dopamine (DA) and serotonin (5-hydroxytryptamine (5-HI)) systems. Second, we will examine the evidence that other substituted phenethylamines are also neurotoxic to certain transmitter systems. Last, we will examine the behavioral and pharmacological consequences of neurotoxicity that result from exposure to some of these amphetamine-related drugs. 

Glennon, R.A, Young, R. Bennington, F. and Morin, R.D. Behavioral and serotonin receptor properties of 4-substituted derivatives of the hallucinogen l-(2,5-dimethoxyphenyl)-2-aminopropane. J Med Chem 25 1163- 1168, 1982. 

Glennon, R.A. and Lucki, I. Behavioral models of serotonin receptor activation. In Sanders-Bush, E., ed. The Serotonin Receptors. Clifton, NJ The Humana Press, 1988. pp. 253-293. 

Moore, R.Y. The anatomy of central serotonergic neuron systems in the rat brain. In Jacobs, B.L., and Gelperin, A., eds. Serotonin Neurotransmission and Behavior. Cambridge, MA MIT Press, 1981. pp. 35-71. 

Rats that have lost dopamine and/or serotonin terminals following treatment with amphetamine, methamphetamine, MDMA, MDA, / -chloroamphetamine, or fenfluramine show little in the way of overt ehanges in appearanee or behavior. Dr. Rieaurte (this volume) emphasized the need for more studies in primates, since MPTP-treated miee also show little in the way of observable functional changes, whereas MPTP-treated monkeys show marked neurologie deficits. It may be neeessary to do more detailed analysis of speeifie behaviors and other funetional outputs that are influeneed by dopamine and/or serotonin neurons, to detect functional deficits induced by some neurotoxic drugs. For instance, specific behaviors sueh as appetite-eontrolled behavior (Leibowitz and Shor-Posner 1986), murieidal behavior (Katz 1980), and sexual behavior (Tucker and File 1983) elieited by drugs... 

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