%0 Journal Article
%T Neuropsychological Functions of ¦Ì- and ¦Ä-Opioid Systems
%A Anna G. Polunina
%A Evgeny A. Bryun
%J ISRN Addiction
%D 2013
%R 10.1155/2013/674534
%X Brain opioid innervation is involved in many pathophysiological processes related to drug addiction. The main idea of the present review is that ¦Ì-/¦Ä-opioid innervation is an intrinsic component of the motor/approach behavior network, which is activated synergetically with dopaminergic mesocorticolimbic network. Contribution of opioid innervation to the motor/approach behavior processing includes generation of positive emotions and inhibition of pain and stress reactions in order that the individual would be able to reach the vital goal. We cite the neuroanatomical data which showed that motor subcortical nuclei contain the most abundant opioid innervation and its activation is an obligatory component of positive emotions. In the majority of life situations, motor/approach behavior network concomitantly activates pain/stress control opioid network. Intensive cognitive activity induces activation of opioid innervation as well, and both enhancing and impairing effects of opioid agonists on cognitive functioning were demonstrated. Overall, the functioning of endogenous opioid networks may be summarized as following: NO physical/cognitive activity£¿=£¿NO positive emotions plus NO pain/stress control. We suppose that contemporary findings concerning neuropsychological functions of endogenous opioid system explain many controversial issues in neuropsychiatric conditions predisposing to drug addiction and neurological mechanisms of opioid addiction. 1. Introduction Brain opioid innervation is intrinsically involved in many pathophysiological processes related to drug addiction. Multiple experimental studies showed that endogenous opioid system is not only the target of opioid addictive drugs but is also activated during alcohol and psychostimulants consumption [1, 2]. Moreover, genetic characteristics of endogenous brain opioid system are an important factor predisposing to drug abuse and addiction. In addicted populations, the frequency of G allele of -opioid receptor is almost twice as high as in healthy populations [3, 4], and the efficacy of detoxification of alcoholic patients with G allele was shown to be lower in comparison with A/A genotype [5]. Ray and colleagues [6] observed higher levels of vigor and lower levels negative mood in alcoholics with Asp40 allele of the -opioid receptor gene in comparison with alcoholics who were homozygotes for the Asn40 variants. Association between cocaine addiction and polymorphism of -opioid receptor was shown in humans as well [7]. Insufficient activity of endogenous brain opioid systems appears to predispose to drug
%U http://www.hindawi.com/journals/isrn.addiction/2013/674534/