RESUMEN
College students (12 female, 12 male) were assigned to either higher caffeine user (HCU) or lower caffeine user (LCU) groups based on a caffeine usage survey. Prior to testing, subjects ingested either placebo or 195 or 325 mg caffeine. They then performed a visual vigilance task measuring response blocks, discrete responses (hits and false alarms), reaction times, and a Mood Check List using a double-blind design. HCU made significantly fewer hits, more false alarms, and also responded faster than LCU. No significant main effects of caffeine administration were found. In the mood analyses, male subjects were more anxious at the end of the experiment. Overall, the user factor (HCU versus LCU) was the most potent experimental variable.
Asunto(s)
Atención/efectos de los fármacos , Cafeína/farmacología , Percepción Visual/efectos de los fármacos , Adolescente , Adulto , Método Doble Ciego , Emociones/efectos de los fármacos , Femenino , Humanos , MasculinoRESUMEN
Noise-dependent effects of smoking multiple cigarettes on subjective state and blood concentrations of ACTH, beta-endorphin, cortisol, and glucose were assessed in a repeated measures design where noise level (high versus minimal) was crossed with nicotine dose (quasi-ad lib own brand versus 1.0 mg FTC nicotine machine-delivered dose versus 0.05 mg FTC nicotine machine-delivered dose). Cortisol and ACTH were increased by nicotine, but not by noise and there was no noise by dose interaction. In contrast, nicotine did not increase beta-endorphin in either noise condition and there was no dose by noise interaction for beta-endorphin. However, noise was associated with a modest increase in beta-endorphin. The effects of nicotine on blood glucose varied as a function of the number of cigarettes smoked. However, the effects of nicotine on glucose, hormones, and subjective state did not vary as a function of noise stress.
Asunto(s)
Hormona Adrenocorticotrópica/sangre , Afecto/efectos de los fármacos , Glucemia/análisis , Hidrocortisona/sangre , Nicotina/farmacología , Ruido , Fumar/efectos adversos , betaendorfina/sangre , Adulto , Humanos , Masculino , Fumar/psicologíaRESUMEN
Two experiments assessed subjective and hormonal effects of smoking cigarettes with three different nicotine deliveries. In experiment 1, 12 males smoked two cigarettes on three different occasions: (1) nicotine-free; (2) their own brand (1.0 mg FTC-estimated nicotine delivery); or (3) 2.4 mg FTC nicotine cigarettes. In experiment 2, 12 males smoked cigarettes of comparable nicotine yield using a quantified smoke delivery system (QSDS). Blood was sampled 2 min after each cigarette completion. Relative to nicotine-free smoking, plasma beta-endorphin (BE) and serum cortisol concentrations increased after quasi-ad libitum smoking of 2.4 mg, but not after 1.0 mg nicotine cigarettes. Self-reported malaise (nausea, sickness, and unpleasantness) also increased after smoking 2.4 mg nicotine cigarettes; subjective distress was correlated with changes in blood BE and cortisol. Smoking 1.0 mg cigarettes did not increase BE or cortisol, or subjective distress. QSDS smoking produced hormonal and subjective effects similar to quasi-ad libitum smoking; however, correlations between neuromodulator concentrations and mood were non-significant. These findings suggest that the elevated levels of plasma BE and cortisol reported in some smoking studies may not be characteristic effects of normal smoking.
Asunto(s)
Hidrocortisona/sangre , Fumar/sangre , betaendorfina/sangre , Adulto , Afecto/efectos de los fármacos , Monóxido de Carbono/sangre , Relación Dosis-Respuesta a Droga , Humanos , Masculino , Neurotransmisores/sangre , Nicotina/sangre , Fumar/efectos adversos , Fumar/psicologíaRESUMEN
Male transgenic (TG) mice overexpressing the human placental growth hormone (GH) variant gene (hGH-V) exhibit reproductive deficits in spite of normal testosterone levels and normal sperm counts. To evaluate the relationship of copulatory behaviors to fertility, we first measured mount, intromission, and ejaculation indices in 2-5-month-old mice (10 TG and 10 normal litter mate controls) during 1 hour tests with ovariectomized, estrogen-, and progesterone-primed females. After eight tests, each male was housed with three intact females for 27 consecutive days. Females were checked daily for vaginal plugs and sacrificed 14 days after insemination to determine the numbers of corpora lutea and live and dead fetuses. Relative to their normal siblings, TG mice mounted less often and intromitted sooner after the initial mount, made marginally more intromissions (with and without ejaculation), and were slower to ejaculate. In subsequent fertility tests, TG males inseminated fewer females and sired fewer live fetuses per insemination than non-TG controls. Across TG and normal males, the length of interval between initial mount and initial intromission was inversely correlated with the number of live offspring sired. This suggests that reduced fertility in hGH-V transgenic male mice may be related to altered copulatory behavior, including a rapid progression from first mount to first intromission.
Asunto(s)
Fertilidad/genética , Regulación de la Expresión Génica/fisiología , Hormona de Crecimiento Humana/genética , Hormonas Placentarias/genética , Conducta Sexual Animal/fisiología , Animales , Humanos , Modelos Logísticos , Masculino , Ratones , Ratones Transgénicos , Reproducción/fisiologíaRESUMEN
Among homeothermic animals, larger species generally have lower metabolic rates and live longer than do smaller species. Because Ames dwarf mice (dwarfs) live approximately 1 year longer than their larger normal sex- and age-matched siblings (normals), we hypothesized that they would have lower body core temperature (Tco). We, therefore, measured Tco of six dwarfs and six normals during 24-h periods of ad lib feeding, 24-h food deprivation, and emotional stress induced by cage switching. With ad lib feeding, Tco of dwarfs averaged 1.6 degrees C lower than normals; during food deprivation, Tco of both dwarfs and controls was significantly lower than when food was available ad lib; and following cage switch, Tco was elevated in both groups. However, during all three experiments, Tco was significantly lower in dwarfs than in normals. These data support the hypothesis that Ames dwarf mice, which live longer than normal size controls, maintain lower Tco than normals. Because dwarfs are deficient in thyroid stimulating hormone (TSH) and growth hormone (GH), their low Tco may be a result of reduced thermogenesis due to lack of those hormones. However, whether low Tco per se is related to the increased longevity of the dwarf mice remains an interesting possibility to be investigated.
Asunto(s)
Constitución Corporal/fisiología , Temperatura Corporal/fisiología , Enanismo Hipofisario/fisiopatología , Longevidad/fisiología , Metabolismo/fisiología , Análisis de Varianza , Animales , Femenino , Privación de Alimentos/fisiología , Genotipo , Ratones , Ratones Mutantes , Descanso/fisiología , Especificidad de la Especie , Estrés Psicológico/fisiopatologíaRESUMEN
Male Sprague Dawley rats were tested for open field ambulation and rearing, and for wheelrunning, following repeated injections of either caffeine or nicotine, given according to a Latin Square design. Caffeine enhanced ambulation and rearing at 5 and 15 mg/kg, IP, and increased wheelrunning with 15 and 45 mg/kg. Nicotine (0.63 mg/kg) also enhanced ambulation, but not rearing, and depressed wheelrunning during the first 20 min of testing. Caffeine's enhancement of wheelrunning was not significant during the first two drug administrations. Results suggest that caffeine and nicotine affect activity via different neuropharmacological mechanisms. Previous experience with these drugs may modulate animals' reactivity to them.
Asunto(s)
Conducta Animal/efectos de los fármacos , Cafeína/farmacología , Nicotina/farmacología , Animales , Conducta Exploratoria/efectos de los fármacos , Locomoción/efectos de los fármacos , Masculino , Actividad Motora/efectos de los fármacos , Ratas , Ratas EndogámicasRESUMEN
The effects of smoking normal-nicotine-delivery cigarettes on serum cortisol, plasma beta-endorphin (BE), and mood were measured in 8 male and 8 female smokers; 8 male and 8 female nonsmokers served as sham-smoking controls. Smoking five cigarettes of the smokers' usual type after overnight deprivation, either ad lib or via a quantified smoke delivery system, produced small but reliable elevations in serum cortisol concentrations; BE was elevated somewhat after two, but not after four or five cigarettes. Smoking-induced elevations in serum cortisol were correlated with decreases in self-reported drowsiness after two and five cigarettes. Additionally, female smokers reported more drowsiness at baseline and after smoking nicotine-free cigarettes than did male smokers or female nonsmokers. Results suggest that smoking-induced elevations in serum cortisol, which persist for at least the first five cigarettes of the day, may modulate the arousing effects of smoking under conditions of low arousal. Also, nicotine-deprived female smokers may experience subnormal arousal compared to male smokers or female nonsmokers.
Asunto(s)
Hormonas/sangre , Fumar/psicología , Adulto , Afecto/efectos de los fármacos , Nivel de Alerta/efectos de los fármacos , Electroencefalografía/efectos de los fármacos , Femenino , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Hidrocortisona/sangre , Masculino , Nicotina/sangre , Factores Sexuales , Fumar/sangre , betaendorfina/sangreRESUMEN
Male Sprague-Dawley reats were trained to bar press for food reinforcement on an FI-300 sec schedule. Ketamine (7.5 mg/kg, IP) significantly increased response rates of both drug-naive and drug-experienced rats for the first 10 min after injection. With a 15.0 mg/kg dose of ketamine, response rates decreased significantly during the first 10 min after injection, irrespective of prior drug experience, but increased significantly above control thereafter in drug-experienced animals. Both doses of ketamine enhanced spontaneous locomotor activity significantly, irrespective of prior drug experience. Differences in the time course and dose dependency of these effects suggest that ketamine stimulates schedule-controlled responding and spontaneous locomotor activity via different neuropharmacologic mechanisms.
Asunto(s)
Condicionamiento Operante/efectos de los fármacos , Ketamina/farmacología , Actividad Motora/efectos de los fármacos , Animales , Masculino , Ratas , Esquema de Refuerzo , Factores de TiempoRESUMEN
A new, automated system for administering quantified doses of cigarette smoke to human subjects is described and results of two studies demonstrating the reliability and validity of the system are presented. To overcome the large variability in nicotine and tar delivery associated with previous means of controlling smoke delivery, an automated quantified smoke delivery system was constructed. The system increases the precision and reliability of the smoke and nicotine dose delivered to human subjects. The quantified smoke delivery system was found to deliver doses of nicotine with a substantially greater degree of precision than procedures typically used in previous laboratory studies of smoking behavior.
Asunto(s)
Nicotina/administración & dosificación , Fumar/sangre , Administración por Inhalación , Adulto , Diseño de Equipo , Estudios de Evaluación como Asunto , Humanos , Masculino , Persona de Mediana Edad , Nicotina/sangreRESUMEN
Male Sprague-Dawley rats were tested for wheelrunning following repeated injections of caffeine or distilled water after varying amounts of experience with caffeine and wheelrunning. Rats experienced with caffeine in combination with wheelrunning ran significantly more than rats experienced only with caffeine or wheelrunning alone. Results suggest that caffeine's stimulant effects are greater when subjects are experienced with wheelrunning while under the influence of the drug.
Asunto(s)
Cafeína/farmacología , Actividad Motora/efectos de los fármacos , Animales , Masculino , Ratas , Ratas Endogámicas , Factores de TiempoRESUMEN
Twenty-four male Sprague-Dawley rats were tested for wheelrunning in conjunction with chronic (continuous) or subchronic (alternate day) oral caffeine administration. As expected, chronic administration led to complete tolerance to caffeine's locomotor stimulant effect, while subchronic administration produced sensitization. Results confirm earlier reports of enhanced stimulation with spaced administration of caffeine and tolerance with chronic administration.
Asunto(s)
Cafeína/farmacología , Actividad Motora/efectos de los fármacos , Administración Oral , Animales , Cafeína/administración & dosificación , Ingestión de Líquidos , Tolerancia a Medicamentos , Distribución Aleatoria , Ratas , Ratas EndogámicasRESUMEN
Transgenic mice overexpressing the phosphoenolpyruvate carboxykinase/bovine growth hormone (PEPCK/bGH) hybrid gene and normal (nontransgenic) littermate controls (10 males + 10 females/group) were given access to tapwater and an ascending series of concentrations of ethanol (1.0-22.0%), then a similar ascending series of concentrations of nicotine (1.0-40.0 micrograms/ml), in a two-bottle choice test. Male transgenic mice consumed more and exhibited greater preferences for ethanol and nicotine than control males; transgenic females consumed less and showed lower preferences for ethanol, but not nicotine, than control females. These results suggest that chronic exposure to high levels of bGH may modulate the rewarding effects of ethanol and nicotine in mice in a gender-specific fashion.
Asunto(s)
Consumo de Bebidas Alcohólicas/genética , Conducta de Elección , Regulación de la Expresión Génica , Hormona del Crecimiento/genética , Nicotina/administración & dosificación , Animales , Bovinos , Femenino , Masculino , Ratones , Ratones Transgénicos , Autoadministración , Caracteres SexualesRESUMEN
Using a two-bottle choice paradigm, adult C57BL/6 and DBA/2 mice (11 males an 10 females per strain) were given access to tapwater and an ascending series of concentrations of ethanol, nicotine, amphetamine, and th artificial sweetener, aspartame. The C57 mice consumed more ethanol, nicotine, and amphetamine, and showed greater preferences for these substances, than did the DBA/2 mice. In contrast, DBAs consumed more and showed greater preference for aspartame than C57s. However, measures of drug and aspartame consumption and preference were moderately intercorrelated when the effects of gender and strain were controlled for. This pattern of results suggests that factors modulating differences between C57BL/6 and DBA/2 mice in ethanol consumption and preference also modulate differences in consumption of nicotine and amphetamine.
Asunto(s)
Anfetamina/administración & dosificación , Aspartame/administración & dosificación , Conducta de Elección/efectos de los fármacos , Etanol/administración & dosificación , Conducta Alimentaria/efectos de los fármacos , Nicotina/administración & dosificación , Administración Oral , Animales , Relación Dosis-Respuesta a Droga , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos DBA , Autoadministración , Caracteres Sexuales , Especificidad de la EspecieRESUMEN
Changes in task-related mood and physiology associated with 31 days of smoking abstinence were assessed in smokers, 34 of whom were randomly assigned to a quit group and 22 to a continuing-to-smoke control group. A large financial incentive for smoking abstinence resulted in very low participant attrition. Individuals were tested during prequit baselines and at 3, 10, 17, and 31 days of abstinence. Abstinence was associated with decreases in heart rate and serum cortisol, a slowing of electroencephalogram (EEG) activity, and task-dependent and trait-depression-dependent hemispheric EEG asymmetries. Differences between the quit group and the smoking group showed no tendency to resolve across the 31 days of abstinence. Trait depression and neuroticism correlated with increases in left-relative-to-right frontal EEG slow-wave (low alpha) activity at both 3 and 31 days of abstinence. In contrast, prequit nicotine intake and Fagerström Tolerance scores correlated with alpha asymmetry and with greater EEG slowing only at Day 3. Thus, the effects of smoking abstinence appear to last for at least several months.
Asunto(s)
Afecto/fisiología , Trastorno Depresivo/psicología , Electroencefalografía/efectos de los fármacos , Nicotina/farmacología , Agonistas Nicotínicos/farmacología , Cese del Hábito de Fumar/psicología , Trastornos Relacionados con Sustancias/psicología , Adulto , Afecto/efectos de los fármacos , Ritmo alfa/efectos de los fármacos , Cafeína/farmacología , Estimulantes del Sistema Nervioso Central/farmacología , Cotinina/farmacología , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Hidrocortisona/sangre , Masculino , Encuestas y Cuestionarios , Ritmo Teta/efectos de los fármacosRESUMEN
The effects of smoking a cigarette or wearing a transdermal nicotine patch on mood and lexical decision-making were tested in eight smokers. Each participant was tested after 4 hours of smoking abstinence, under 4 conditions: placebo (very low nicotine) cigarette, nicotine cigarette, placebo patch, and nicotine patch. Relative to placebo, wearing the nicotine patch reduced Profile of Mood States (POMS) Total Mood Disturbance and Fatigue/Inertia scores, while increasing the speed of some types of lexical decisions. Smoking a nicotine cigarette did not affect reaction times, but unexpectedly decreased the accuracy of Word/ Nonword lexical decisions. Thus, transdermal nicotine may improve mood and facilitate longterm memory search and/or attentional processes in nicotine-deprived smokers.
Asunto(s)
Afecto/efectos de los fármacos , Toma de Decisiones/efectos de los fármacos , Nicotina/administración & dosificación , Aprendizaje por Asociación de Pares/efectos de los fármacos , Tiempo de Reacción/efectos de los fármacos , Cese del Hábito de Fumar , Administración Cutánea , Adolescente , Adulto , Nivel de Alerta/efectos de los fármacos , Atención/efectos de los fármacos , Femenino , Humanos , MasculinoRESUMEN
10 habitual smokers, aged 19-25 yr., were randomly assigned to smoke either a very low nicotine "Placebo" cigarette (.05-mg nicotine delivery as estimated by the FTC method) or a Nicotine cigarette (.7-mg estimated nicotine delivery). Each participant was asked to abstain from smoking for 4 to 7 hr. prior to testing. After completing a presmoking test of lexical decision-making, participants smoked either a Nicotine or Placebo cigarette and were then retested for reaction times and accuracy on the lexical decision test. When presented the most difficult lexical decisions, participants responded significantly faster after smoking a Nicotine cigarette than they did before smoking; smoking a Placebo cigarette did not affect reaction times. Response accuracy was unaffected by smoking either kind of cigarette. These results suggest that smoking a nicotine cigarette may improve attention or memory retrieval after several hours of smoking abstinence.
Asunto(s)
Toma de Decisiones , Lenguaje , Fumar/psicología , Conducta Verbal , Adulto , Femenino , Humanos , MasculinoRESUMEN
Male Sprague-Dawley rats were trained to barpress under a FL-300 sec schedule of food presentation until responding patterns were stable. The effects of the ketamine optical isomers (enantioners) on this schedule-controlled behavior were examined over a dose range of 3.75 to 60 mg/kg i.p. At doses of 15 mg/kg and above, (-)-ketamine increased rate of responding, with a maximum increase of about 3 times control rate. This effect was rate-dependent, being more marked at lower control rates. In contrast (+)-ketamine did not increase overall fixed-interval response rate at any dose, but decreased rate of responding in a rate-dependent fashion at doses of 30 mg/kg and above. Spontaneous locomotor activity was increased about equally by equimolar doses of both enantiomers.