Enhancing VTA Cav1.3 L-type Ca2+ channel activity promotes cocaine and mood-related behaviors via overlapping AMPA receptor mechanisms in the nucleus accumbens.

Genetic factors significantly influence susceptibility for substance abuse and mood disorders. Rodent studies have begun to elucidate a role of Cav1.3 L-type Ca2+ channels in neuropsychiatric-related behaviors, such as addictive and depressive-like behaviors. Human studies have also linked the CACNA1D gene, which codes for the Cav1.3 protein, with bipolar disorder. However, the neurocircuitry and the molecular mechanisms underlying the role of Cav1.3 in neuropsychiatric phenotypes are not well established. In the present study, we directly manipulated Cav1.3 channels in Cav1.2 dihydropyridine insensitive mutant mice and found that ventral tegmental area (VTA) Cav1.3 channels mediate cocaine-related and depressive-like behavior through a common nucleus accumbens (NAc) shell calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (CP-AMPAR) mechanism that requires GluA1 phosphorylation at S831. Selective activation of VTA Cav1.3 with (±)-BayK-8644 (BayK) enhanced cocaine conditioned place preference and cocaine psychomotor activity while inducing depressive-like behavior, an effect not observed in S831A phospho-mutant mice. Infusion of the CP-AMPAR-specific blocker Naspm into the NAc shell reversed the cocaine and depressive-like phenotypes. In addition, activation of VTA Cav1.3 channels resulted in social behavioral deficits. In contrast to the cocaine- and depression-related phenotypes, GluA1/A2 AMPARs in the NAc core mediated social deficits, independent of S831-GluA1 phosphorylation. Using a candidate gene analysis approach, we also identified single-nucleotide polymorphisms in the CACNA1D gene associated with cocaine dependence in human subjects. Together, our findings reveal novel, overlapping mechanisms through which VTA Cav1.3 mediates cocaine-related, depressive-like and social phenotypes, suggesting that Cav1.3 may serve as a target for the treatment of neuropsychiatric symptoms.

Intention to adhere to HIV treatment: a patient-centred predictor of antiretroviral adherence.

OBJECTIVES: Despite the effectiveness of highly active antiretroviral therapy (HAART), HIV remains a major cause of mortality in the USA, largely as a result of poor HIV treatment adherence. In this study we assessed the association between five patient-centred factors and adherence to HIV treatment. METHODS: We surveyed 244 adults at two HIV clinics in Houston, Texas between October 2009 and April 2010. Participants were given a questionnaire and their charts were reviewed for clinical data. Survey items assessed the following factors: self-assessed HIV knowledge, awareness of disease biomarkers, intention to adhere to HIV treatment, health literacy and decision-making style. The primary outcome measure was HAART adherence during the previous month. Logistic regressions were performed to calculate the effect of each factor on adherence. RESULTS: All participants had HIV/AIDS and were on HAART at enrolment. Eight per cent of participants were female, 57% were African-American and 16% were Hispanic. Mean age was 58.1 years. Sixty-eight per cent were adherent to HAART during the last month. On univariate analysis, a preference for wanting choices, correct knowledge of recent HIV viral load level, and intention to adhere to HIV treatment were significantly associated with adherence. On multivariate analysis, only intention to adhere to HIV treatment remained statistically significant after adjusting for other factors (odds ratio 2.2; 95% confidence interval 1.1 to 4.3). CONCLUSIONS: Intention to adhere to HIV treatment was significantly associated with self-reported adherence to HAART. Interventions that bolster patients' intentions to adhere to HIV treatment during clinical encounters may improve adherence to HAART and HIV control.

Impact of antiretroviral dosing frequency and pill burden on adherence among newly diagnosed, antiretroviral-naive HIV patients.

There are few data on the impact of antiretroviral therapy (ART) regimen factors on adherence in ART-naïve HIV patients on contemporary once- or twice-daily regimens. Ninety-nine newly diagnosed patients in a prospective observational cohort study completed a visual analogue scale to assess their ART adherence. Adherence by type of ART and dosing frequency were compared by Brown-Mood median tests. Participants taking once-daily regimens had higher adherence (n = 70, 99.5%) compared with participants taking twice-daily regimens (n = 29, 94%; P = 0.01). Adherence of participants taking the fixed dose combination efavirenz-emtricitabine-tenofovir (n = 34, 100%) compared with those taking once-daily regimens of two or more pills was no different (n = 36, 99.3%; P = 0.34). Among a cohort of newly diagnosed ART-naïve patients, once-daily dosing of ART resulted in higher adherence than twice-daily dosing. Pill burden among once-daily regimens did not predict adherence, suggesting that factors other than pill burden should drive regimen selection.

Spinal mediators that may contribute selectively to antinociceptive tolerance but not other effects of morphine as revealed by deletion of GluR5.

Several groups maintain that morphine tolerance and dependence correlate with increased activity of protein kinases ERK1/2 and P38 MAPK and PKC as well as elevated levels of the neuropeptides dynorphin (DYN), substance P (sP), and calcitonin gene-related peptide (CGRP) in spinal cord dorsal horn (SCDH). They demonstrate that tolerance and dependence can be prevented, and sometimes reversed, by constitutive genetic deletion or pharmacological inhibition of these factors. Recently, we showed that mice with a constitutive deletion of the GluR5 subunit of kainate receptors (GluR5 KO) are not different from wild type (WT) littermates with respect to baseline nociceptive thresholds as well as acute morphine antinociception, morphine physical dependence and conditioned place preference. However, unlike WT, GluR5 KO mice do not develop antinociceptive tolerance following systemic morphine administration. In this report, we examined levels of these mediators in SCDH of WT and GluR5 KO mice following subcutaneous implantation of placebo or morphine pellets. Surprisingly, spinal DYN and CGRP, along with phosphorylated ERK2 (pERK2), P38 (pP38) and PKCgamma (pPKCgamma) are elevated by deletion of GluR5. Additionally, chronic systemic morphine administration increased spinal pERK2, pP38 and pPKCgamma levels in both tolerant WT and non-tolerant GluR5 KO mice. In contrast, while morphine increased spinal DYN and CGRP in WT mice, DYN remained unchanged and CGRP was reduced in GluR5 KO mice. These observations suggest that spinal ERK2, P38 and PKCgamma are likely involved in multiple adaptive responses following systemic morphine administration, whereas DYN and CGRP may contribute selectively to the development of antinociceptive tolerance.

Psychiatric disorders, HIV infection and HIV/hepatitis co-infection in the correctional setting.

Psychiatric disorders such as bipolar disorder, schizophrenia and depression have long been associated with risk behaviors for HIV, hepatitis C virus (HCV) and hepatitis B virus (HBV). The US prison population is reported to have elevated rates of HIV, hepatitis and most psychiatric disorders. This study examined the association of six major psychiatric disorders with HIV mono-infection, HIV/HCV co-infection and HIV/HBV co-infection in one of the nation's largest prison populations. The study population consisted of 370,511 Texas Department of Criminal Justice inmates who were incarcerated for any duration between January 1, 2003 and July 1, 2006. Information on medical conditions and sociodemographic factors was obtained from an institution-wide electronic medical information system. Offenders diagnosed with HIV mono-infection, HIV/HCV, HIV/HBV and all HIV combined exhibited elevated rates of major depression, bipolar disorder, schizophrenia, schizoaffective disorder, non-schizophrenic psychotic disorder and any psychiatric disorder. In comparison to offenders with HIV mono-infection, those with HIV/HCV co-infection had an elevated prevalence of any psychiatric disorder. This cross-sectional study's finding of positive associations between psychiatric disease and both HIV infection and hepatitis co-infection among Texas prison inmates holds both clinical and public health relevance. It will be important for future investigations to examine the extent to which psychiatric disorders serve as a barrier to medical care, communication with clinicians and adherence to prescribed medical regimens among both HIV-mono-infected and HIV/hepatitis-co-infected inmates.

The validity of viral hepatitis and chronic liver disease diagnoses in Veterans Affairs administrative databases.

BACKGROUND: The validity of International Classification of Diseases-9 codes for liver disease has not been determined. AIM: To examine the accuracy of International Classification of Diseases-9 codes for cirrhosis with hepatitis C virus or alcoholic liver disease and HIV or hepatitis B virus coinfection with hepatitis C virus in Veterans Affairs data. METHODS: We conducted a retrospective study comparing the Veterans Affairs administrative data with abstracted data from the Michael E. DeBakey VA Medical Center's medical records. We calculated the positive predictive value, negative predictive value, per cent agreement and kappa. RESULTS: For cirrhosis codes, the positive predictive value (probability that cirrhosis is present among those with a code) and negative predictive value (probability that cirrhosis is absent among those without a code) were 90% and 87% with 88% agreement and kappa = 0.70. For hepatitis C virus codes, the positive predictive value and negative predictive value were 93% and 92%, yielding 92% agreement and kappa = 0.78. For alcoholic liver disease codes, the positive predictive value and negative predictive value were 71% and 98%, with 89% agreement and kappa = 0.74. All parameters for HIV coinfection with hepatitis C virus were >89%; however, the codes for hepatitis B virus coinfection had a positive predictive value of 43-67%. CONCLUSION: These diagnostic codes (except hepatitis B virus) in Veterans Affairs administrative data are highly predictive of the presence of these conditions in medical records and can be reliably used for research.

Internet use among low-income persons recently diagnosed with HIV infection.

Patients are increasingly using the Internet to obtain health-related information, communicate with providers and access research. Use of the Internet to obtain health-related information by low-income patients recently diagnosed with HIV infection has not been examined. In 2005, we surveyed 126 low-income patients diagnosed with HIV infection within the last three years. Eighty-five percent of the patients were<50 years old, 63% were male, 68% were minority race, 27% were Hispanic and 61% acquired HIV through heterosexual intercourse. Twenty-eight percent never completed high school and 74% earned<$15,000 in 2004. While 89% indicated they would like to use the Internet to access information about HIV, 52% had never used the Internet, 28% had never used it to obtain health-related information and only 18% had done so at least monthly for the last six months. Two-thirds of the population studied would need instruction on how to use the Internet. In multivariable regression, 2004 income > or =$15,000 predicted monthly Internet use to obtain health-related information. Older age, heterosexual intercourse as HIV risk factor and inadequate health literacy were independent predictors of needing instruction. The low-income population with HIV infection lags behind the general population in Internet access and may not benefit from Internet-dependent advances in health communication, including HIV-related interventions.

Up-regulation of dopamine D(2)L mRNA levels in the ventral tegmental area and dorsal striatum of amphetamine-sensitized C57BL/6 mice: role of Ca(v)1.3 L-type Ca(2+) channels.

Dopamine D(2) long (D(2)L) and D(2) short (D(2)S) isoforms of the D(2) receptor play an important role in psychostimulant-induced neuronal adaptations. In this study, we used quantitative real-time PCR to specifically amplify these two splice variants to examine their mRNA expression in the dorsal striatum (dStr), nucleus accumbens (NAc) and the ventral tegmental area (VTA) of amphetamine-sensitized C57BL/6 mice. We found a significant increase in D(2)L mRNA in the VTA and dStr of amphetamine-treated mice that positively correlated with the sensitized locomotor response. We also found a significant increase in D(2)S mRNA in the VTA. We further examined the role of the Ca(v)1.3 subtype of L-type Ca(2+) channels in up-regulation of D(2)L and D(2)S mRNA in the VTA. Amphetamine-pretreated Ca(v)1.3 wild-type (Ca(v)1.3(+/+)) mice exhibited sensitized behavior and a significant increase in D(2)L and D(2)S mRNA compared with saline-pretreated mice Amphetamine-pretreated homozygous Ca(v)1.3 knockout (Ca(v)1.3(-/-)) mice did not exhibit sensitized behavior. There was a significant increase in D(2)S mRNA, but not D(2)L mRNA. In conclusion, our results find that amphetamine increases D(2)L mRNA expression in the dStr and the VTA, an adaptation that correlates with expression of sensitized behavior and dependence on Ca(v)1.3 Ca(2+) channels.