The effect of environment on the changes in calmodulin in rat brain produced by repeated amphetamine treatment

EEG ALPHA SENSITIZATION IN INDIVIDUALIZED HOMEOPATHIC TREATMENT OF FIBROMYALGIA

Fibromyalgia (FM) patients show evidence of sensitizability in pain pathways and electroencephalographic (EEG) alterations. One proposed mechanism for the claimed effects of homeopathy, a form of complementary medicine used for FM, is time-dependent sensitization (TDS, progressive amplification) of host responses. This study examined possible sensitization-related changes in EEG relative alpha magnitude during a clinical trial of homeopathy in FM. A 4-month randomized, placebo-controlled double-blind trial of daily orally administered individualized homeopathy in physician-confirmed FM, with an additional 2-month optional crossover phase, included three laboratory sessions, at baseline, 3 and 6 months (N = 48, age 49.2 +/- 9.8 years, 94% women). Nineteen leads of EEG relative alpha magnitude at rest and during olfactory administration of treatment and control solutions were evaluated in each session. After 3 months, the active treatment group significantly increased, while the placebo group decreased, in global alpha-1 and alpha-2 during bottle sniffs over sessions. At 6 months, the subset of active patients who stayed on active continued to increase, while the active-switch subgroup reversed direction in alpha magnitude. Groups did not differ in resting alpha. Consistent with the TDS hypothesis, sniff alpha-1 and alpha-2 increases at 6 months versus baseline correlated with total amount of time on active remedy over all subjects (r = 0.45, p = .003), not with dose changes or clinical outcomes in the active group. The findings suggest initiation of TDS in relative EEG alpha magnitude by daily oral administration of active homeopathic medicines versus placebo, with laboratory elicitation by temporolimbic olfactory stimulation or sniffing.

The roles of calcium/calmodulin-dependent and Ras/mitogen-activated protein kinases in the development of psychostimulant-induced behavioral sensitization

Although the development of behavioral sensitization to psychostimulants such as cocaine and amphetamine is confined mainly to one nucleus in the brain, the ventral tegmental area (VTA), this process is nonetheless complex, involving a complicated interplay between neurotransmitters, neuropeptides and trophic factors. In the present review we present the hypothesis that calcium-stimulated second messengers, including the calcium/calmodulin-dependent protein kinases and the Ras/mitogen-activated protein kinases, represent the major biochemical pathways whereby converging extracellular signals are integrated and amplified, resulting in the biochemical and molecular changes in dopaminergic neurons in the VTA that represent the critical neuronal correlates of the development of behavioral sensitization to psychostimulants. Moreover, given the important role of calcium-stimulated second messengers in the expression of behavioral sensitization, these signal transduction systems may represent the biochemical substrate through which the transient neurochemical changes associated with the development of behavioral sensitization are translated into the persistent neurochemical, biochemical and molecular alterations in neuronal function that underlie the long-term expression of psychostimulant-induced behavioral sensitization.

Repeated cocaine administration alters the expression of genes in corticolimbic circuitry after a 3-week withdrawal: a DNA macroarray study

Addiction to psychostimulants elicits behavioral and biochemical changes that are assumed to be mediated by alterations of gene expression in the brain. The changes in gene expression after 3 weeks of withdrawal from chronic cocaine treatment were evaluated in the nucleus accumbens core and shell, dorsal prefrontal cortex and caudate using a complementary DNA (cDNA) array. The level of mRNA encoded by several genes was identified as being up- or down-regulated in repeated cocaine versus saline subjects. The results from the cDNA array were subsequently confirmed at the protein level with immunoblotting. Of particular interest, parallel up-regulation in protein and mRNA was found for the adenosine A1 receptor in the accumbens core, neuroglycan C in the accumbens shell, and the GluR5 glutamate receptor subtype in dorsal prefrontal cortex. However, there was an increase in TrkB protein in the nucleus accumbens core of cocaine-treated rats without a corresponding alteration in mRNA. These changes of gene expression in corticolimbic circuitry may contribute to the psychostimulant-induced behavioral changes associated with addiction.

Developmental sources of variation in liability to adolescent substance use disorders

This review provides a synthesis of the literature on the complex sequence of maturational, psychosocial, and neuroadaptive processes that lead to substance use disorders (SUD) in adolescence. A brief overview introduces the concepts of liability to SUD and epigenesis. A theory is presented explaining how affective, cognitive, and behavioral dysregulation in late childhood is exacerbated during early and middle adolescence by family and peer factors, as well as puberty, leading to substance use. Continued exacerbation of the three components of dysregulation by drug and non-drug stressors during late adolescence is posited to result in neuroadaptations that increase the likelihood of developing SUD, particularly in high-risk individuals. Implications for etiologic research as well as clinical and preventive interventions are discussed.

Differential regulation of calmodulin content and calmodulin messenger RNA levels by acute and repeated, intermittent amphetamine in dopaminergic terminal and midbrain areas

Repeated doses of psychoactive drugs often produce adaptive responses that differ from the initial drug application and additional adaptive processes occur following cessation of the drug. The relationship between alterations in calmodulin protein and messenger RNA produced by an initial versus a repeated dose of amphetamine was examined, as well as changes following drug cessation. Calmodulin protein and messenger RNA of the three individual calmodulin genes were measured in rat dopaminergic cell body and terminal areas following acute or repeated amphetamine. Rats were either injected once with 2.5mg/kg amphetamine or saline and decapitated after 3h, or given 10 injections of amphetamine three to four days apart and decapitated 3h after the final injection. Calmodulin messenger RNA and protein were also measured three and seven days after ceasing drug treatment. Acute amphetamine increased calmodulin 1.7-fold in the striatum and threefold in the ventral mesencephalon, with corresponding elevations in calmodulin messenger RNAs. In response to the 10th dose of amphetamine, however, the degree of increase in calmodulin was diminished in the striatum and ablated in the ventral mesencephalon. Correspondingly, select species of calmodulin messenger RNA were decreased from control levels. In the frontal cortex or nucleus accumbens, calmodulin levels were basically unaltered by the first or 10th doses of amphetamine, but both calmodulin and its messenger RNA were altered with time upon cessation of the drug. Three days later, both calmodulin protein and messenger RNA were decreased in select brain areas. By seven days after the 10th injection, calmodulin content was altered compared to saline controls in all areas, but the change in messenger RNA no longer paralleled the change in protein.Our findings demonstrate that both calmodulin protein and select species of calmodulin messenger RNA are altered by acute amphetamine, but this effect is attenuated after repeated, intermittent amphetamine. There are further time-dependent changes after cessation of repeated amphetamine, which may reflect compensatory neuronal responses. The alterations in calmodulin content and synthesis could contribute to changes in patterns or duration of behaviors that occur upon cessation of repeated amphetamine.

Alterations in calmodulin mRNA expression and calmodulin content in rat brain after repeated, intermittent amphetamine

To assess whether calmodulin (CaM) gene expression could have a role in behavioral sensitization induced by repeated, intermittent amphetamine, CaM protein and mRNA of the three separate CaM genes were measured in several different brain areas from rats repeatedly administered saline or amphetamine. Rats were injected twice weekly for five weeks, followed by one week of withdrawal. CaM protein and mRNA were measured in dorsal striatum, limbic forebrain, prefrontal cortex, ventral mesencephalon and piriform cortex. There were increases of CaM protein content and decreases of CaM I mRNA in the dorsal striatum and prefrontal cortex. CaM II mRNA was also decreased in the dorsal striatum. A decrease of CaM protein and an increase of CaM I mRNA were found in the ventral mesencephalon. There was no change of CaM protein in the limbic forebrain, although a decrease of CaM I mRNA was detected. CaM protein and mRNA were not altered in the piriform cortex. Our findings demonstrate that both CaM content and mRNA are altered after an amphetamine regimen leading to sensitization. The fact that the changes in CaM content and mRNA are in dopaminergic brain areas associated with sensitization suggests that CaM could contribute to neurochemical events underlying behavioral sensitization to amphetamine.