Interaction of 5-HT2A and 5-HT2C receptors in R(-)-2,5-dimethoxy-4-iodoamphetamine-elicited head twitch behavior in mice

Drug-elicited head-twitch behavior is a useful model for studying hallucinogen activity at 5-HT(2A) receptors in the mouse. Chemically diverse compounds active in this assay yield biphasic dose-effect curves, but there is no compelling explanation for the "descending" portion of these functions. A set of experiments was designed to test the hypothesis that the induction of head-twitch behavior is mediated by agonist actions at 5-HT(2A) receptors, whereas the inhibition of head-twitch behavior observed at higher doses results from competing agonist activity at 5-HT(2C) receptors. The effects of the phenethylamine hallucinogen R(-)-2,5-dimethoxy-4-iodoamphetamine (DOI) on head-twitch behavior were studied over a range of doses in the mouse, generating a characteristic biphasic dose-response curve. Pretreatment with the selective 5-HT(2A) antagonist (+)-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenylethyl)]-4-piperidine-methanol (M100907) shifted only the ascending limb of the DOI dose-effect function, whereas pretreatment with the nonselective 5-HT(2A/2C) antagonist 3-{2-[4-(4-fluorobenzoyl)piperidin-1-yl]ethyl}quinazoline-2,4(1H,3H)-dione (ketanserin) produced a parallel shift to the right in the DOI dose-response curve. Administration of the 5-HT(2C) agonist S-2-(chloro-5-fluoro-indol-l-yl)-1-methylethylamine (Ro 60-0175) noncompetitively inhibited DOI-elicited head-twitch behavior across the entire dose-effect function. Finally, pretreatment with the selective 5-HT(2C) antagonists 6-chloro-5-methyl-1-[(2-[2-methylpyrid-3-yloxy]pyrid-5yl)carbamoyl]indoline (SB242084) or 8-[5-(2,4-dimethoxy-5-(4-trifluoromethylphenylsulfonamido)phenyl-5-oxopentyl]-1,3,8-triazaspiro[4,5]decane-2,4-dione hydrochloride (RS 102221) did not alter DOI-elicited head-twitch behavior on the ascending limb of the dose-response curve but shifted the descending limb of the DOI dose-response function to the right. The results of these experiments provide strong evidence that DOI-elicited head-twitch behavior is a 5-HT(2A) agonist-mediated effect, with subsequent inhibition of head-twitch behavior being driven by competing 5-HT(2C) agonist activity.

Distress, denial, and low adherence to behavioral interventions predict faster disease progression in gay men infected with human immunodeficiency virus

This study examined psychological prediction of 2-year disease progression in gay men after finding out their human immunodeficiency virus (HIV) serostatus. Psychological and immune status of asymptomatic gay men who did not know their HIV serostatus was monitored during the 5 weeks before and after serostatus notification. The men were randomly assigned to an exercise. cognitive-behavioral stress-management intervention, or control group. At 2-year follow-up for the 23 men who turned out to be seropositive. 9 had developed symptoms, including 5 with acquired immune deficiency syndrome--4 of whom died. Distress at diagnosis, denial (5 weeks post-diagnosis minus pre-diagnosis). and low adherence during interventions were significant predictors of 2-year disease progression. Denial and adherence remained significant predictors of disease progression even after controlling for CD4 number at entry. Furthermore. change in denial was significantly correlated with immune status 1 year later; l-year immune status was significantly correlated with 2-year disease progression. The present study therefore demonstrates significant relations between psychological variables on the one hand and both immune measures and HIV-1 disease progression on the other. We conclude that distress, denial, and low protocol compliance predict subsequent disease progression.

Sleep disturbances in men with asymptomatic human immunodeficiency (HIV) infection

During the clinical latency phase of human immunodeficiency virus (HIV) disease the central nervous system may be infected and begin to manifest subtle dysfunction. Our early investigations demonstrated persistent alterations in the sleep architecture of HIV-infected asymptomatic men. The major aims of this study were to delineate alterations of sleep architecture in asymptomatic HIV-infected men, to identify and describe sleep behavior complaints and to seek a correlation between objective sleep parameters and subjective complaints of sleep behavior. The study sample consisted of 24 men, 14 HIV-infected and 10 HIV-negative, age-matched controls. The protocol included a comprehensive history and physical, two polysomnograms, urine toxicity, detailed written sleep questionnaire, the Pittsburgh Sleep Quality Index, the Spielberger State-Trait Anxiety Test and the Beck Depression Inventory. Our results indicated that sleep architecture differed from controls in that wakefulness, slow-wave sleep [SWS-stage 3 and 4 nonrapid eye movement (NREM) sleep] and stage rapid eye movement (REM) sleep were more evenly dispersed throughout the night. In particular, SWS was prevalent during the second half of recorded sleep. The observed changes in the NREM/REM cycle could not be explained on the basis of underlying psychopathology. Just as the course of individuals with HIV infection varies, it is expected that sleep abnormalities will vary. Considering the known relationships between NREM stage 3 and 4 and immune system function, it is possible that the observed alterations in the NREM/REM cycle are related to coincident changes in immunologic function. Quantitative measures of NREM sleep, especially SWS and REM sleep, are perhaps of greater significance than relative measures of sleep stages.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunologic function in a cohort of human immunodeficiency virus type 1-seropositive and -negative healthy homosexual men

The study objectives were to determine the early effects of human immunodeficiency virus type 1 (HIV-1) infection on both phenotypic and functional immunologic markers in healthy homosexual men, to ascertain the relationships of these markers to each other, and to discover which markers were affected by enrollment in an AIDS study in which HIV-1 serostatus would be determined. The major findings were as follows. (i) The CD4/CD8 ratio and lymphocyte proliferative response to pokeweed mitogen were the characteristics most affected by early HIV-1 infection. (ii) The loss in CD4 cells observed in the HIV-1-positive homosexual men was entirely due to diminished numbers of the memory subset. CD4+ CD29+. The reciprocal subset of CD4, CD4+ CD45RA+, did not differ in the two groups of homosexual men at either time point or in the controls. (iii) Prior to learning their HIV-1 serostatus, HIV-1 antibody-negative risk-group males had lower phytohemagglutinin (PHA) responses than the controls did. In the assays following notification of their seronegativity, however, these men had PHA values which were not different from those of the controls. In the HIV-1-positive group, the responses to both PHA and pokeweed mitogen were below those of both HIV-1-negative groups and did not change after serostatus notification. (iv) The activity of natural killer cells was lower in the risk-group men than in the controls at both pre- and postdiagnosis but was not related to HIV-1 serostatus. (v) In this cohort of homosexual men, the CD4/CD8 ratio correlated significantly with the functional measures of immunologic status in the HIV-1-positive men, but not in the HIV-1-negative men.