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A review on alcohol: from the central action mechanism to chemical dependency
Rev Assoc Med B ras 2015; 61(4):381-387 381
REVIEW ARTICLE
A review on alcohol: from the central action mechanism to
chemical dependency
João V ictor Vezali Costardi 1, Rafael Augusto Teruaki Nampo1, Gabriella Lourenço Silva1, Maria Aparecida F erreira Ribeiro2,
Heryck José Stella3, Mercia Breda Stella4, Sônia V aléria P inheiro Malheiros5*
1Medical Student, Faculdade de Medicina de Jundiaí, Jundiaí, SP, Brazil
2MSc – Adjunct Professor, Centro Universitário Padre Anchieta, Jundiaí, SP, Brazil
3MSc – Assistant Professor, Faculdade de Medicina de Jundiaí, Jundiaí, SP, Brazil
4PhD – Adjunct Professor, Faculdade de Medicina de Jundiaí, Jundiaí, SP, Brazil
5Post-doctorate in Biochemistry, Adjunct Professor, Faculdade de Medicina de Jundiaí. Adjunct Professor at Universidade Metodista de Piracicaba (UNIMEP), Piracicaba, SP, Brazil
Summary
Study conducted at the Faculdade de
Medicina de Jundiaí, Jundiaí, SP, Brazil
Article received: 9/19/2014
Accepted for publication: 10/22/2014
*Correspondence:
Address: Rua Francisco Telles, 250
Vila Arens
Jundiaí, SP – Brazil
Mail Box 1295
Postal code: 13202-505
+55 11 4587-1095
Introduction: alcohol is a psychotropic depressant of the central nervous system
(CNS) that promotes simultaneous changes in several neuronal pathways, exert-
ing a profound neurological impact that leads to various behavioral and biologi-
cal alterations.
Objectives: to describe the effects of alcohol on the CNS, identifying the signal-
ing pathways that are modified and the biological effects resulting from its con-
sumption.
Methods: a literature review was conducted and articles published in different
languages over the last 15 years were retrieved.
Results: the studies reviewed describe the direct effect of alcohol on several neu-
rotransmitter receptors (gamma-aminobutyric acid [GABA], glutamate, endocan-
nabinoids AEA and 2-AG, among others), the indirect effect of alcohol on the lim-
bic and opioid systems, and the effect on calcium and potassium channels and on
proteins regulated by GABA in the hippocampus.
Discussion and conclusion: the multiple actions of alcohol on the CNS result
in a general effect of psychomotor depression, difficulties in information storage
and logical reasoning and motor incoordination, in addition to stimulating the
reward system, a fact that may explain the development of addiction. Knowledge
on the neuronal signaling pathways that are altered by alcohol allows the identi-
fication of effectors which could reduce its central action, thus, offering new ther-
apeutic perspectives for the rehabilitation of alcohol addicts.
Keywords: alcohol-induced disorders, nervous system, neurotransmitter receptors.
Introduction
The alcohol found in beverages such as wine and beer is
chemically classified as ethanol. Ethanol consists of a
chain of two carbons and a hydroxyl group (-OH). These
characteristics confer a perfect hydrophilic-hydropho-
bic balance which, together with the low weight of the
molecule,1 guarantees an immense capacity for diffu-
sion and distribution in all body fluids and tissues, fa-
voring its partitioning in the central nervous system
(CNS).2
The effects of alcohol on the individual and its capac-
ity to alter behavior have been known since the beginning
of its consumption by different societies. Although alco-
hol is not classically viewed as a drug in Brazil, it is con-
sidered as a psychotropic CNS depressant and its con-
sumption is one of the highest among all psychoactive
substances, a fact that has numerous consequences.
The objective of this study was to perform an exten-
sive, but not necessarily comprehensive, literature review
of the effects of alcohol on the CNS, describing the neu-
ronal changes induced by alcohol, as well as biological
and behavioral effects that can explain the development
of chemical dependency and contribute to the elabora-
tion of new therapeutic measures.