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Abstract: Background: Environmental factors such as early drug exposure influence drug abuse vulnerability, and evidence also suggests that drug abuse is highly heritable. The purpose of the present study was to determine whether environmental and genetic factors interact to produce additive drug abuse vulnerability. Methods: An animal model of relapse was used to examine the effects of adolescent nicotine exposure on adult cocaine seeking in rats bred for high (HiS) and low (LoS) saccharin intake. Rats from HiS and LoS progenitor lines received s.c. injections of nicotine for 10 days (postnatal days 22–31). Rats were then allowed to reach adulthood and were trained to lever press for cocaine infusions. During each self-administration session, the house light (HL) was illuminated and each lever press activated a set of lights adjacent to the lever (LL). Following cocaine self-administration, the HL and LL were deactivated, cocaine solutions were replaced with saline, and rats extinguished lever pressing. Subsequently, rats were tested under a multi-component reinstatement procedure consisting of: (1) cue-induced reinstatement with LL alone and the HL presented alone, (2) cocaine-induced reinstatement without LL and HL present, (3) and cocaine-induced reinstatement with LL present. Results: The results indicated that adolescent nicotine exposure sensitized the reinstatement of cocaine seeking during adulthood in HiS (but not LoS) rats when lever pressing resulted in LL cue presentations. In addition, following administration of the cocaine priming injection, rats exposed to nicotine (vs. saline) during adolescence (LoS and HiS) engaged in more cocaine seeking under the cocaine-primed reinstatement condition when lever pressing illuminated the LL. Conclusion: These results suggest that drug abuse vulnerability may be a function of early life exposure to drugs of abuse in addition to genetic influences. [Copyright &y& Elsevier]

Background: Preference for sweet-tasting foods, weight gain, and constipation characterize patients receiving methadone maintenance treatment (MMT). The prevalence of constipation in MMT and its relation to preference for sweet taste and body mass index (BMI) are undetermined.Methods: A random sample of 83 patients was interviewed for constipation with the Patient Assessment Constipation Quality of Life (PAC-QOL) questionnaire. They rated taste intensity and reward of sweet, salty, and sour solutions by means of a nine-point Likert scale. Data on their BMI, drugs in urine, methadone dose, and serum levels were analyzed.Results: Forty-two patients reported minimum to severe constipation. They characterized as having longer durations of opioid usage before MMT and worse sleep quality than non-constipated patients (logistic regression). Constipation intensity was inversely correlated with duration in MMT and linearly correlated with the Patient Assessment Constipation Quality of Life score. Patients with constipation rated reward to sweet taste significantly higher with no differences in taste intensity compared to non-constipated patients. Patients with high methadone serum levels (≥750 ng/mL) rated taste intensity significantly lower compared to those with normal methadone serum levels (<750 ng/mL), and the lowest rates were reported among patients with no constipation and high methadone serum levels.Conclusions: Constipation was highly prevalent among MMT patients and associated with poor sleep and lower quality of life. The relation to preference for sweets, as reflected by higher reward rating, strongly supports the need for nutritional intervention to alleviate constipation symptoms and improve quality of life and sleep. [ABSTRACT FROM AUTHOR]

Abstract: Risk factors that predict vulnerability for nicotine and other drug abuse have been identified using preclinical models, and there is close agreement with clinical and epidemiological studies. The major risk factors to be discussed are age, sex/hormonal status, impulsivity, sweet-liking, novelty reactivity, proclivity for exercise, and environmental impoverishment (vs. enrichment). This discussion will focus on factors that preclinical research has determined are strong and translatable predictors of nicotine and other drug abuse. An advantage of using preclinical models is that prospective, longitudinal studies and within-subject designs can be used to reveal risk factors that are diverse yet maintain unique characteristics. The many interrelationships among these factors lead to an additive vulnerability that increases the predictability that drug abuse will occur. A feature that these risk factors have in common is that they consistently predict vulnerability to drug abuse over critical transition phases of addiction that are difficult to examine prospectively in humans, such as acquisition, escalation, and reinstatement of drug-seeking after abstinence (relapse). The models offer valuable information that has been transferred to effective prevention and treatment strategies for smoking and other drug abuse in humans. [Copyright &y& Elsevier]