Faculty Bibliography

Previous studies in female rats have shown that estrogen increases preproenkephalin (PPE) mRNA levels in the ventrolateral part of the ventromedial nucleus of the hypothalamus (VMHVL), an area implicated in the modulation of sexual behavior. In order to assess the physiological role of hypothalamic opioid expression in lordosis reflex 16-mer oligodeoxynucleotide (ODN) directed towards the PPE mRNA were acutely microinjected above the VMH of estradiol-primed ovariectomized rats. Estradiol-induced lordosis behavior was observed in response to a stud male 2 days thereafter. Antisense (without or with 4 mismatches) ODN injections near the VMHVL resulted in a significant reduction in lordosis quotient compared to control (reverse sense) ODN treatment or to antisense ODN injections targeted anterior or posterior to the VMHVL. In contrast, locomotor activity of these animals in the open-field test was not affected by ODN treatments. Enkephalin immunoreactive levels were determined by radioimmunoassay in the preoptic area, a major terminal field of the VMHVL. Estradiol-induced enkephalin levels were greatly reduced in antisense-treated groups. Using the in situ hybridization technique, PPE mRNA levels in the VMHVL were also determined. A 1.5-2-fold increase in PPE mRNA levels was observed in estradiol-treated rats compared to ovariectomized rats as previously described. This increase in PPE mRNA levels was not affected by ODN treatment, suggesting that the reduction of enkephalin expression was mainly due to physical blockade of PPE mRNA translation and not to its degradation. Taken together, these data further support the behavioral role of PPE expressing VMHVL neurons. They also highlight the in vivo potency of acute administration of antisense phosphorothioate ODNs in blocking neuronal target gene expression

It was previously observed that the corticosteroid synthesis inhibitor, aminoglutethimide (AG), markedly facilitates lateral hypothalamide (AG), markedly facilitates lateral hypothalamic self-stimulation (LHSS) in food-restricted rats. This effect is not present 30 min after injection when plasma corticosterone levels are suppressed, but rather at 2 h when corticosterone has recovered from suppression. In experiment 1, it was confirmed that AG (50.0 mg/kg, s.c.) lowers the threshold for LHSS in food-restricted rats but not in control rats that have ad libitum access to food. This effect occurred independently of whether food restriction, by itself, lowered threshold. Experiment 2 examined whether the facilitation of LHSS coincides with biosynthetic rebound of corticosteroid precursors. While a pregnenolone surge was demonstrated by radioimmunoassay, dose-response testing with exogenous pregnenolone and progesterone (0.1, 1.0 and 10.0 mg/kg, s.c.) failed to confirm the prediction that one of these precursors facilitates reward. Therefore, a general test of the involvement of adrenocortical biosynthetic events was conducted in experiment 3 where rats were adrenalectomized (ADX) or sham-operated prior to food restriction. Surprisingly, ADX did not diminish the effect of AG. This finding raises the possibility of a CNS, rather than adrenal, site of action. AG is known to penetrate the blood-brain barrier and exert weak anticonvulsant effects. The facilitation of reward may result from central inhibitory effects of the drug and share a common basis with the enhanced reinforcing potency of other CNS depressants in food-restricted rats

Nine VA Medical Centers are participating in a 2-year double-blind placebo controlled study of antioxidant treatment for tardive dyskinesia (TD) conducted by the Department of Veteran Affairs Cooperative Studies Program. One of the principal outcome measures of this study is the score derived from the instrumental assessment of upper extremity dyskinesia. Dyskinetic hand movements are quantified by assessing the variability associated with steady-state isometric force generated by the patient. In the present report, we describe the training procedures and results of a multi-center reliability assessment of this procedure. Data from nine study centers comprising 45 individual patients with six trials each (three from left hand and three from right hand) were reanalyzed by an independent investigator and the results were subjected to reliability assessment. For the statistic of interest (average coefficient of variation over trials 2 and 3 for each hand, then take the larger of these two values), we found very high intraclass correlation coefficients for reliability over all patients across sites (ICC = 0.995). We also calculated the reliability of the measures across trials within patient for each combination of hand (right, left, dominant), rater group (site, control), and trials set (all three, trials 2 and 3). For a given hand and trial set, the reliability of the site raters was similar to that of the control. This study demonstrates that instrumental measures for the assessment of dyskinesia are reliable and can be implemented in multi-center studies with minimal training

It was previously reported that chronic food restriction and streptozotocin-induced diabetes lead to brain region-specific changes in levels of Prodyn-derived peptides. These changes parallel behavioral adaptations that are reversed by opioid antagonists. In the present study, effects of food restriction and diabetes on Prodyn gene expression were measured in rat brain regions using a quantitative solution hybridization mRNA assay. Picogram amounts of Prodyn mRNA were determined in extracts of five brain regions. The highest density of Prodyn mRNA was observed in extracts of nucleus accumbens (4.68 pg/microg total RNA), bed nucleus of the stria terminalis (4.18 pg/microg), and in caudate nucleus (3.51 pg/microg). Lower levels were observed in the lateral hypothalamus (1.87 pg/microg) and central nucleus of the amygdala (1.22 pg/microg). Food restriction and diabetes both markedly increased the levels of Prodyn mRNA in the central amygdala (163% and 93%, respectively). Levels in the lateral hypothalamus were also increased (35% and 29%, respectively), though only the food-restriction effect was statistically significant. Neither treatment altered prodynorphin mRNA levels in the caudate nucleus, nucleus accumbens or bed nucleus of the stria terminalis. These results suggest that dynorphin neurons in central amygdala and lateral hypothalamus may be involved in behavioral or physiological adaptations to sustained metabolic need

An emerging body of evidence indicates that the adrenal hormone corticosterone modulates behavioral effects of abused drugs. Recently, it was reported that the self-administration and locomotor stimulatory effect of cocaine are blocked by adrenalectomy (ADX). In order to evaluate the effect of ADX on the brain reward system in general, and cocaine reward in particular, the effect of ADX on lateral hypothalamic self-stimulation (LHSS) and its facilitation by cocaine were investigated. Using curve-shift methodology, effects of cocaine (1.0, 3.0 and 10.0 mg/kg, i.p.) on the rewarding efficacy of brain stimulation were determined in ADX rats, with and without corticosterone supplementation, and compared with sham-operated controls. Results indicate that ADX does not affect LHSS or the facilitatory effect of cocaine. The divergence between these results and the results of cocaine self-administration studies is discussed in terms of the neuroanatomical and psychological processing of reward

This article describes a standardized method for establishing and maintaining desired levels of interrater reliability (IRR) in multicenter trials. The procedure involves six steps: distribution of procedural guides, distribution of an introduction tape, initial distribution of patient interviews to rate, training at the study kickoff meeting, ongoing IRR monitoring, and group training throughout the study. This method is being used in a national Veterans Affairs Cooperative Study (CS #394), involving nine sites to examine the treatment effects of vitamin E on tardive dyskinesia. The six-step standardized process allowed for early detection of areas of concern in assessment administration. When comparing intraclass correlation coefficients (ICCs) at different points in the initial training, the Barnes Akathisia Scale and Anchored Brief Psychiatric Rating Scale reliability improved from 0.68 to 0.74 and from 0.54 to 0.87, respectively. After analyzing the ratings collected prior to the start of CS #394, data were collected to conduct the first check on Abnormal Involuntary Movement Scale (AIMS) IRR during enrollment; the estimated ICC for the AIMS had decreased from 0.87 to 0.60. Raters were instructed to re-assess the subjects from the first videotape on the AIMS and received additional training. The re-rating indicated very good reliability, 0.84, IRR was measured once for the Global Assessment of Functioning Scale resulting in an ICC of 0.90. The companion article (Part II: Edson et al. 1997, page 59 of this issue) describes the statistical procedures used to measure IRR

The primary goal of Veterans Affairs (VA) Cooperative Study (CS) #394 is to determine if vitamin E is a safe and efficacious treatment for tardive dyskinesia (TD). The study uses various instruments to assess subjects for movement disorders (Abnormal Involuntary Movement Scale [AIMS], and Barnes Akathisia Scale [BAS]), psychopathology (Anchored Brief Psychiatric Rating Scale [BPRS]), and level of functioning (Global Assessment of Functioning scale [GAF]). Since the study involves nine sites, each with its own set of raters, it is important to establish and maintain high interrater reliability (IRR) on these instruments throughout the study and to identify raters who differ significantly from the others. To make this determination, personnel at each site assessed subjects from standardized videotapes on the AIMS, BAS, and Anchored BPRS, and rated written vignettes on the GAF. We fit these data to a two-way additive model to identify nonstandardized raters (i.e., those whose average ratings were significantly lower or higher than the others, or those whose scores, after adjusting for subject and rater effects, were highly variable). The proportion of nonstandardized raters ranged from 7 percent (Anchored BPRS) to 33 percent (AIMS). The estimated intraclass correlation coefficients (ICCs) indicated moderate reliability for the AIMS, BAS, and Anchored BPRS (0.73 to 0.75) and excellent agreement for the GAF (0.90). The companion article (Part I: Tracy et al. 1997, page 53 of this issue) describes the procedures used to train the raters for this study