RESUMO
AIMS: Animal studies have shown that nicotine releases dopamine, a neurotransmitter implicated in drug reinforcement. We hypothesized that bromocriptine would decrease smoking behavior in humans. DESIGN: The study was conducted double blind and subjects' order of dose exposure was randomized. PARTICIPANTS: The smoking behavior of 20 heavy smokers was recorded for 5 hours after ingesting placebo or one of two doses of bromocriptine (2.50 mg, 3.75 mg) over three sessions (one dose per session). FINDINGS: There was a significant negative linear trend by dosage indicating shorter total puffing time with increasing bromocriptine dosages (p < 0.02). Other significant negative linear trends by increasing dosage include fewer number of puffs, fewer number of cigarettes smoked and mean latency to smoke after 3 hours (expected CMAX on the drug (all ps < 0.05). There was a negative significant linear trend showing decreased plasma nicotine (p < 0.02) and cotinine (p < 0.005) with increasing dosages of bromocriptine. Shiffman/Jarvik Withdrawal Scale (SJWS) cigarette craving subscale scores decreased significantly across increasing dosages (linear trend p < 0.02). There was a significant negative linear trend (p < 0.05) on the Profile of Mood States (POMS) Vigor and Depression subscales, with subjects reporting decreased vigor and depression with increasing bromocriptine doses. No other mood effects were observed. CONCLUSION: These results support the hypothesis that dopaminergic mechanisms mediate cigarette smoking reinforcement.
Assuntos
Bromocriptina/administração & dosagem , Agonistas de Dopamina/administração & dosagem , Abandono do Hábito de Fumar/métodos , Adolescente , Adulto , Análise de Variância , Bromocriptina/efeitos adversos , Bromocriptina/uso terapêutico , Cotinina/sangue , Agonistas de Dopamina/efeitos adversos , Agonistas de Dopamina/uso terapêutico , Método Duplo-Cego , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos do Humor/etiologia , Náusea/etiologia , Nicotina/sangue , Autorrevelação , Abandono do Hábito de Fumar/psicologiaRESUMO
This study examined cigarette craving and blood nicotine levels in 11 male heavy smokers who were observed during 16 h of tobacco abstinence. Subjects rated their urge to smoke on a new brief 10-item questionnaire, Urge to Smoke (UTS), Schuh and Stitzer's four-item Visual Analog Scale (SSI), and a Strength of Urge to Smoke (SUTS) item. Testing occurred: 1) after 16 h (1700 h the night before to 0900 h the next morning) of abstinence from smoking; 2) after an ad lib smoking period following the 16 h abstinence; 3) every hour during 6 hours of abstinence; 4) and finally, after the 6 h abstinence, another ad lib smoking period. Thus, subjects smoked twice in each session. Blood plasma nicotine levels were measured before, after, and every 2 h during the 6-h abstinence period for a total of six measures. Blood pressure and heart rate were measured prior to each blood draw. There was a significant negative correlation between blood nicotine levels and craving for cigarettes on all craving questionnaires (rs = -0.55 to -0.78; ps < 0.002). Carbon monoxide was shown to correlate highly with nicotine blood levels (rs = 0.83 to 0.98 across subjects; ps < 0.001). Results are consistent with the hypothesis that "urge to smoke" reflects nicotine seeking in continuing smokers.
Assuntos
Comportamento Aditivo , Nicotina/sangue , Fumar/sangue , Adulto , Comportamento Aditivo/sangue , Humanos , Projetos Piloto , Fumar/psicologia , Abandono do Hábito de Fumar/psicologia , Síndrome de Abstinência a Substâncias/sangue , Síndrome de Abstinência a Substâncias/psicologia , Inquéritos e Questionários , Fatores de TempoRESUMO
Nonsmokers and smokers were compared for olfactory sensitivity to two odors associated with cigarettes: nicotine and menthol. Smokers were tested twice--while nonabstinent, and after 16-20 h of smoking abstinence. Smokers showed a higher olfactory threshold for nicotine than did nonsmokers, but the same threshold for menthol. Furthermore, when the smokers were abstinent, they showed a lower olfactory threshold for nicotine than when they were nonabstinent, but again, the same threshold for menthol. These results suggest a nicotine specific olfactory deficit in smokers that is reduced during abstinence.