Dopamine transporter and D 2 -receptor density in late-onset alcoholism

Abstract

Striatal presynaptic DAT densities are decreased among type 1 alcoholics, and this finding is not associated with recent alcohol abuse.

Dopamine D2/D3-receptor and transporter densities in nucleus accumbens and amygdala of type 1 and 2 alcoholics

“…23,[27][28][29][30] Because of the relatively low spatial resolution of in vivo imaging methods, it has been difficult to differentiate nucleus accumbens from the dorsal striatum, and earlier results have indicated changes in the nigrostriatal system (ie, substantia nigra, nucleus caudatus, putamen, globus pallidus), which has been implied in the control of movement and may not be as important as the mesolimbic system in the context of addiction. 10,[12][13][14][15] Aside from our preliminary results, regarding DAT in the nucleus accumbens of seven type 1 alcoholics and healthy controls, 30 there are no other reports on DA D 2 /D 3 receptor and DAT densities in the nucleus accumbens or amygdala of human alcoholics. The aim of this study was to compare the DA D 2 /D 3 receptor and transporter densities in the nucleus accumbens and amygdala in alcoholics classified as type 1 or 2, according to Cloninger, 9 and healthy controls.…”

“…[43][44][45][46] PET and functional studies have indicated some evidence to suggest that decreased DAT and DA D 2 receptor densities in type 1 alcoholics are not merely a consequence of recent alcohol abuse but, at least to some extent, a trait marker for alcoholism. 12,19 Thus, our findings may reflect some genetic or developmental variability that is related to addiction vulnerability. Further studies are needed to clarify the extent of this apparent deficit in DA receptor densities in alcoholics, and if they are more related to variations in neurodevelopment or chronic alcohol exposure, and to what extent these variables apply to DA D 2 /D 3 receptors and DAT.…”

“…There are several human 10,[12][13][14][15][16] and animal [38][39][40] alcohol preferring animals, and no reports have found changes in K d . Therefore, we chose ligand concentration to be close to K d , in order to optimize binding dynamics.…”

“…This is in contrast to the observed serotonergic deficit in early-onset type 2 alcoholism, which is characterized by novelty seeking, impulsive behavior and social hostility. 9 Preliminary results from positron emission tomographic (PET) and single photon emission tomographic (SPET) studies have indicated alterations in either dopamine transporter (DAT) densities or presynaptic DA function in the striatum of type 1 alcoholics [10][11][12] and in unclassified (type 1 vs type 2) alcoholics, 13 although contradictory results have also been reported in a study of unclassified alcoholics. 14 Other articles have reported low DA D 2 receptor densities in the striatum of unclassified alcoholics [14][15][16] and endocrinological measurements have shown decreased DA mediated activity among unclassified alcoholics.…”

Dopamine Transporter in vitro Binding and in vivo Imaging in the Brain

“…The dopamine transporter is therefore an important element for the action of dopamine on locomotion, cognition, affect and neuroendocrine functions (Giros & Caron 1993;Hoffman 1994;Vizi 2000). Alterations in dopamine transporter have been described in several neurologic and neuropsychiatric disorders (Verhoeff 1999) such as Parkinson's disease (Janowsky et al 1987), Alzheimer's disease (Allard et al 1990), depression (Laasonen-Balk et al, 1999), alcoholism (Tiihonen et al 1995;Laine et al 1999;Repo et al 1999;Tupala et al 2000), schizophrenia (Laakso et al 2000a(Laakso et al & 2001, attention deficit hyperactivity disorder (Krause et al 2000), and social phobia (Tiihonen et al 1997). This review deals with in vitro and in vivo imaging methods for studying the dopamine transporter distribution and function.…”