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Scientists have long sought the mechanisms by which alcohol acts on the brain to modify behavior. An important finding is the demonstration that alcohol can affect the function of specific neurotransmitters1 (Lovinger et al. 1989). Studies of neurotransmitters and the receptors to which they bind have provided data on both the structure and the mechanism of action of these molecules as well as clues to their role in behavior. However, the function of individual neurotransmitters and their receptors cannot entirely explain a syndrome as complex as alcoholism.
In this neurodegenerative disorder, the decline begins with the dopamine-producing cells in the brain where movement is coordinated. As these cells degrade, motor function is compromised, which https://ecosoberhouse.com/ includes tremors, rigidity, bradykinesia or slowed movement, as well as changes in speech and gait. Drugs currently used to treat ADHD do indeed increase the effectiveness of dopamine.
Short-term exposure to intoxicating concentrations of alcohol appears to inhibit both NMDA and non-NMDA receptor activity, potentially resulting in sedation (Valenzuela and Harris 1997). As in the case of GABAA receptors, however, these excitatory receptors are relatively alcohol and dopamine insensitive to intoxicating concentrations of alcohol under some experimental conditions (Wright et al. 1996), underscoring the need for more research in this area. The fourth pathway which interests us and is of note for alcohol addiction is the pathway of glutamate.
Investigators have postulated that tolerance is regulated by connections between neurons that produce multiple neurotransmitters or neuromodulators (Kalant 1993). For example, evidence indicates that vasopressin (a pituitary hormone with effects on body fluid equilibrium) plays an important role in maintaining tolerance to alcohol (Tabakoff and Hoffman 1996). Remarkably, a single exposure to a vasopressinlike chemical while an animal is under the effects of alcohol is followed by long-lasting tolerance to alcohol (Kalant 1993). The development of this long-lasting tolerance depends not only on vasopressin but also on serotonin, norepinephrine, and dopamine—neurotransmitters with multiple regulatory functions (Tabakoff and Hoffman 1996; Valenzuela and Harris 1997). Alcohol might induce sedative effects by reducing excitatory neurotransmission. The major excitatory neurotransmitters in the brain are the amino acids aspartate and glutamate, which act through both NMDA receptors—so named because they respond to the synthetic chemical N-methyl-d-aspartate—and non-NMDA receptors.
All of them function both individually and interactively as G-protein coupled receptors. Swedish pharmacologist and neuroscientist Arvid Carlsson won the Nobel prize in 2000 for his research on dopamine, showing its importance in brain function. He helped show that the neurotransmitter is heavily involved in the motor system.
