Selective alleviation of compulsive lever-pressing in rats by D1, but not D2, blockade: possible implications for the involvement of D1 receptors in obsessive-compulsive disorder.
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Rats undergoing extinction of lever-pressing for food after the attenuation of an external feedback for this behavior exhibit excessive lever-pressing unaccompanied by an attempt to collect a reward. This behavior may be analogous to the excessive and unreasonable behavior seen in obsessive-compulsive disorder. In the present study, we tested the hypothesis that the compulsive behavior induced by signal attenuation is mediated via D(1) rather than D(2) receptors. Administration of 0.005, 0.01 and 0.03 mg/kg of the D(1) antagonist SCH 23390 reduced the number of compulsive lever-presses without affecting the number of lever-presses followed by an attempt to collect a reward. In contrast, administration of 0.005, 0.01, 0.024, 0.036 and 0.05 of the D(2) antagonist haloperidol dose-dependently decreased both types of lever-presses. In addition, haloperidol at doses that decreased lever-pressing in the post-training signal attenuation procedure (0.036 and 0.05 mg/kg) had a similar effect in regular extinction, whereas an SCH 23390 dose that decreased compulsive lever-pressing in the post-training signal attenuation procedure (0.01 mg/kg) had no effect on regular extinction. On the basis of electrophysiological data on the response of dopamine neurons to the omission of an expected reward, these results were interpreted as suggesting that compulsive lever-pressing depends on a phasic decrease in the stimulation of D(1) receptors. The implications of these results for the pathophysiology and treatment of obsessive-compulsive disorder are discussed. (+info)
Effect of primary polydipsia on aquaporin and sodium transporter abundance.
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Chronic primary polydipsia (POLY) in humans is associated with impaired urinary concentrating ability. However, the molecular mechanisms responsible for this finding have not been elucidated. The purpose of this study was to examine the effect of chronic primary POLY on water metabolism and renal aquaporin (AQP) water channels and sodium and urea transporter abundance in rats. Primary POLY was induced in male Sprague-Dawley rats by daily administration of 15 g powdered rat chow mixed in 100 ml water for 10 days. Control rats (CTL) received 15 g powdered rat chow per day and ad libitum drinking water. Rats were studied following this period before further intervention and with a 36-h period of water deprivation to examine maximal urinary concentrating ability. At baseline, POLY rats demonstrated significantly greater water intake (100 +/- 1 vs. 22 +/- 2 ml/day, P < 0.0001) and urinary output (80 +/- 1 vs. 11 +/- 1 ml/day, P < 0.0001) and decreased urinary osmolality (159 +/- 13 vs. 1,365 +/- 188 mosmol/kgH2O, P < 0.001) compared with CTL rats. These findings were accompanied by decreased inner medulla AQP-2 protein abundance in POLY rats compared with CTL rats before water deprivation (76 +/- 2 vs. 100 +/- 7% CTL mean, P < 0.007). With water deprivation, maximal urinary osmolality was impaired in POLY vs. CTL rats (2,404 +/- 148 vs. 3,286 +/- 175 mosmol/kgH2O, P < 0.0005). This defect occurred despite higher plasma vasopressin concentrations and similar medullary osmolalities in POLY rats. In response to 36-h water deprivation, inner medulla AQP-2 protein abundance was decreased in POLY rats compared with CTL rats (65 +/- 5 vs. 100 +/- 5% CTL mean, P < 0.0006). No significant differences were noted in renal protein abundance of either AQP-3 or AQP-4 or sodium and urea transporters. We conclude that the impaired urinary concentrating ability associated with primary POLY in rats is due to impaired osmotic equilibration in the collecting duct that is mediated primarily by decreased AQP-2 protein abundance. (+info)
Validity and factor structure of the bodybuilding dependence scale.
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OBJECTIVES: To investigate the factor structure, validity, and reliability of the bodybuilding dependence scale and to investigate differences in bodybuilding dependence between men and women and competitive and non-competitive bodybuilders. METHODS: Seventy two male competitive bodybuilders, 63 female competitive bodybuilders, 87 male non-competitive bodybuilders, and 63 non-competitive female bodybuilders completed the bodybuilding dependence scale (BDS), the exercise dependence questionnaire (EDQ), and the muscle dysmorphia inventory (MDI). RESULTS: Confirmatory factor analysis of the BDS supported a three factor model of bodybuilding dependence, consisting of social dependence, training dependence, and mastery dependence (Q = 3.16, CFI = 0.98, SRMR = 0.04). Internal reliability of all three subscales was high (Cronbach's alpha = 0.92, 0.92, and 0.93 respectively). Significant (p<0.001) and moderate correlations were found between all BDS and MDI subscales, and between five of the eight EDQ subscales. A multivariate analysis of covariance, with univariate F tests and Tukey HSD tests, revealed that both male and female competitive bodybuilders scored significantly (p<0.05) higher on all three BDS subscales than the male and female non-competitive bodybuilders. However, there were no significant sex differences on any of the BDS subscales (p>0.05). CONCLUSION: The three factor BDS appears to be a reliable and valid measure of bodybuilding dependence. Symptoms of bodybuilding dependence are more prevalent in competitive bodybuilders than non-competitive ones, but there are no significant sex differences in bodybuilding dependence. (+info)
Cannabinoid hyperemesis: cyclical hyperemesis in association with chronic cannabis abuse.
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BACKGROUND AND AIMS: To explore the association between chronic cannabis abuse and a cyclical vomiting illness that presented in a series of cases in South Australia. METHODS: Nineteen patients were identified with chronic cannabis abuse and a cyclical vomiting illness. For legal and ethical reasons, all patients were counselled to cease all cannabis abuse. Follow up was provided with serial urine drug screen analysis and regular clinical consultation to chart the clinical course. Of the 19 patients, five refused consent and were lost to follow up and five were excluded on the basis of confounders. The remaining nine cases are presented here and compared with a published case of psychogenic vomiting. RESULTS: In all cases, including the published case, chronic cannabis abuse predated the onset of the cyclical vomiting illness. Cessation of cannabis abuse led to cessation of the cyclical vomiting illness in seven cases. Three cases, including the published case, did not abstain and continued to have recurrent episodes of vomiting. Three cases rechallenged themselves after a period of abstinence and suffered a return to illness. Two of these cases abstained again, and became and remain well. The third case did not and remains ill. A novel finding was that nine of the 10 patients, including the previously published case, displayed an abnormal washing behaviour during episodes of active illness. CONCLUSIONS: We conclude that chronic cannabis abuse was the cause of the cyclical vomiting illness in all cases, including the previously described case of psychogenic vomiting. (+info)
Hypergraphia associated with a brain tumour of the right cerebral hemisphere.
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Two different neurobehavioural abnormalities have been reported under the term hypergraphia. One has been described in temporal lobe epilepsies and the other in the acute stage of strokes of the right cerebral hemisphere. The latter type of hypergraphia in a patient with a metastatic brain tumour confined to the right hemisphere is reported. Such hypergraphia is a general right hemisphere sign that is not peculiar to strokes in the acute stage and the writing behaviour is inattentive. (+info)
Sexual compulsivity among heterosexual college students.
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A growing body of literature suggests that an association exists between sexual compulsivity and participation in sexual behaviors that are high risk in terms of HIV/STD infection. In most of these studies, sexual compulsivity has been measured using the Sexual Compulsivity Scale. As yet, sexual compulsivity has only been assessed with this scale among individuals who are members of high risk groups for HIV infection or who are HIV-positive. In this study, we found support for reliability and construct validity of the SCS in a sample of 876 heterosexual college students, a group not yet examined in the sexual addiction and compulsivity literature. Construct validity was substantiated by the presence of significant relationships of sexual compulsivity with frequencies of sexual behaviors and numbers of sexual partners. The scale was also related to gender and age. Sexual compulsivity scores were associated with frequency of risky sexual behaviors. The relationships between sexual compulsivity and solo, partner, public, and risky sexual behaviors remained significant when we controlled for demographic variables. Although we found support for construct validity of the SCS in our sample, it is not clear whether the scale distinctly measures sexual compulsivity or taps into other constructs, such as sexual desire and sexual exploration. (+info)
The natural history of temporal variant frontotemporal dementia.
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BACKGROUND: The temporal variant of frontotemporal dementia (tvFTD) features asymmetric anterior temporal/amygdala degeneration as well as ventromedial frontal, insular, and inferoposterior temporal involvement. Left temporal atrophy has been linked to loss of semantic knowledge, whereas behavioral symptoms dominate the right temporal variant. OBJECTIVE: To investigate the first symptoms and the timing of subsequent symptoms in patients with left versus right tvFTD. METHODS: Twenty-six patients with tvFTD were identified. Six had right > left temporal atrophy (right temporal lobe variant [RTLV]) and were matched with six having comparable left > right temporal atrophy (left temporal lobe variant [LTLV]). Clinical records were reviewed to generate individualized symptom chronologies. RESULTS: In all patients, first symptoms involved semantics (4/6 LTLV, 1/6 RTLV), behavior (4/6 RTLV, 1/6 LTLV), or both (1 LTLV, 1 RTLV). Semantic loss began with anomia, word-finding difficulties, and repetitive speech, whereas the early behavioral syndrome was characterized by emotional distance, irritability, and disruption of physiologic drives (sleep, appetite, libido). After an average of 3 years, patients developed whichever of the two initial syndromes--semantic or behavioral--that they lacked at onset. A third stage, 5 to 7 years from onset, saw the emergence of disinhibition, compulsions, impaired face recognition, altered food preference, and weight gain. Compulsions in LTLV were directed toward visual, nonverbal stimuli, whereas patients with RTLV were drawn to games with words and symbols. CONCLUSIONS: The temporal variant of frontotemporal dementia follows a characteristic cognitive and behavioral progression that suggests early spread from one anterior temporal lobe to the other. Later symptoms implicate ventromedial frontal, insular, and inferoposterior temporal regions, but their precise anatomic correlates await confirmation. (+info)
Obsessions and compulsions in Asperger syndrome and high-functioning autism.
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BACKGROUND: Obsessive-compulsive behaviours are common and disabling in autistic-spectrum disorders (ASD) but little is known about how they compare with those experienced by people with obsessive-compulsive disorder (OCD). AIM: To make such a comparison. METHOD: A group of adults with high-functioning ASD (n=40) were administered the Yale-Brown Obsessive-Compulsive Scale and Symptom Checklist and their symptoms compared with a gender-matched group of adults with a primary diagnosis of OCD (n=45). OCD symptoms were carefully distinguished from stereotypic behaviours and interests usually displayed by those with ASD. RESULTS: The two groups had similar frequencies of obsessive-compulsive symptoms, with only somatic obsessions and repeating rituals being more common in the OCD group. The OCD group had higher obsessive-compulsive symptom severity ratings but up to 50% of the ASD group reported at least moderate levels of interference from their symptoms. CONCLUSIONS: Obsessions and compulsions are both common in adults with high-functioning ASD and are associated with significant levels of distress. (+info)