Search PubMed⌕ Search

Biomedical subjects

N E Grunberg

Publications and source records attributed to N E Grunberg.

At least 37 records · Page 2Linked to original sources
PubMed1994

Nicotine increases sensory gating measured as inhibition of the acoustic startle reflex in rats.

Chronic nicotine administration has been reported to increase acoustic startle response (ASR) amplitude in rats, which has been offered as evidence that some dosages of nicotine can enhance attention. The present experiments examined effects of acutely administered nicotine on amplitude and pre-pulse inhibition (PPI) of acoustic startle in rats. PPI, the decrease in ASR amplitude by a stimulus preceding the startle-eliciting event, reflects pre-attentive neural processes underlying sensory gating. Nicotine had a biphasic dose effect on startle amplitude, with increases at lower dosages (0.01 mg/kg) and decreases at higher dosages (0.5-5.0 mg/kg SC). Lower dosages of nicotine (0.001-0.01 mg/kg) increased PPI and the increase at 0.001 mg/kg occurred independently of changes in ASR amplitude. These results confirm that increases in PPI are not dependent upon changes in ASR amplitude. Results are consistent with nicotine's enhancements of performance on cognitive tasks in humans and are the first reported use of the PPI paradigm to model such effects. These findings indicate that ASR paradigms are useful to study effects of nicotine.

Acoustic Stimulation↗
PubMed1994

Effects of nicotine on body weight and plasma insulin in female and male rats.

There is an inverse relationship between nicotine and body weight. It has been proposed that this inverse relationship is partially mediated by insulinergic actions, but the effect of nicotine on insulin only has been reported for male rats. The present experiment was designed to examine the effect of nicotine administration on body weight and plasma insulin in female and male rats. In addition, the effects of anesthesia prior to sacrifice on plasma insulin were examined. Nicotine reduced body weight and plasma insulin in female and male rats. In addition, the use of an anesthetic prior to sacrifice was associated with higher plasma insulin levels for male rats. These findings are consistent with the interpretation that insulinergic mechanisms play a role in the nicotine-body weight relationship.

Analysis of Variance↗
PubMed1994

Overview: biological processes relevant to drugs of dependence.

Key points are highlighted from five papers that address biological processes underlying the actions of opiates, CNS stimulants, nicotine, alcohol, and benzodiazepines. It is noteworthy that: (1) positive and negative reinforcement are common processes underlying actions of drugs of dependence; (2) dopaminergic systems in the ventral tegmental area of the brain seem to be involved in the positive reinforcement of drugs of dependence; (3) GABA also may be involved in this positive reinforcement; (4) receptor sensitization and desensitization may be involved in the actions of drugs of dependence; (5) noradrenalin, 5-HT, ACh, NMDA and corticosteroids also may be involved in drug dependence; (6) motivational systems and processes in addition to positive and negative reinforcement deserve increased research attention; and (7) there may be genetic-based individual differences in drug dependence processes.

Animals↗
PubMed1993

Effect of stress on oral fentanyl consumption in rats in an operant self-administration paradigm.

The effect of intermittent footshock stress (0.8 mA; 0.2 s on; 40 s off on the average; for 10 min/day) on oral fentanyl (50 or 75 micrograms/ml) self-administration (SA) in operant chambers was examined in male rats. In Experiment 1, after 1 month of initiation of the fentanyl SA by partial water deprivation, animals were tested for lever-pressing for fentanyl (75 micrograms/ml) under fixed-ratio-4 (FR-4) and progressive-ratio (PR) schedules of reinforcement for 30 min/day in operant chambers. Exposure to footshock stress increased fentanyl SA under the FR-4 and PR schedules compared with a nonstress condition. When water was substituted for the drug, the operant behavior persisted before extinction. In Experiment 2, different rats were tested for lever-pressing for fentanyl (50 micrograms/ml) under FR-6 and PR schedules. This experiment further assessed the role of taste in the stress-induced fentanyl SA and examined the effect of increasing the schedule requirements (i.e., FR-3, 6, and 12) on lever-pressing for fentanyl. Exposure to footshock stress increased lever-pressing for oral fentanyl SA under the FR schedules of reinforcement. When a quinine solution (30 micrograms/ml), matched for bitter taste with the fentanyl solution, was substituted for the drug solution, an extinction of the drug-reinforced behavior occurred, indicating that the stress-induced oral fentanyl SA is not related to stress-induced changes in taste sensitivity. In both experiments, no significant stress effects were observed for water consumption in home cage and lever-pressing on the nonoperative lever.

Animals↗
PubMed1992

Effect of stress on oral morphine and fentanyl self-administration in rats.

The effect of immobilization stress (15 min/day) or no stress on oral morphine (0.25-0.5 mg/ml) or fentanyl (5-20 micrograms/ml) self-administration was examined in rats. Animals had access to a morphine or fentanyl solution for 4 days, followed by a single-choice day of access to the opioid solution and a separate water bottle. This 5-day cycle was repeated five times for 7 h/day in home cages. Morphine consumption and preference were assessed for an additional 30 days (i.e., six more cycles) in a subgroup of subjects. Plasma corticosterone levels in the stress groups indicated that the stress manipulation was effective. Over the course of the experiment, animals in the stress groups significantly increased their preference for the opioid solutions during choice days compared to nonstress controls. Morphine preference after 55 days was twice as high in the stress group (70% morphine/30% water) in comparison to controls (34% morphine/66% water). These results indicate that stress increases oral opioid self-administration in rats. Future directions and the implications of this work are discussed.

Administration, Oral↗
PubMed1992

Effect of stress on hypothalamic insulin in rats.

Four experiments examined the effects of stress on hypothalamic insulin and plasma hormones in rats. Two hours daily of immobilization (IM) stress for 2 and 4 days resulted in an increase in hypothalamic insulin. In contrast, 15 min of daily IM over 13 days or 48 h of continuous signalled shock avoidance did not alter hypothalamic insulin. These findings are interpreted to indicate that changes in hypothalamic insulin are part of the stress response. Possible reasons for the different effects of time and paradigm on the hypothalamic insulin responses to stress are discussed. Plasma insulin and glucose levels were not responsive to any of the stressors. Brief acute stress caused increases in the stress-responsive hormones ACTH, corticosterone, and prolactin, as expected, and these responses attenuated or disappeared with repeated or longer stress exposures.

Adrenocorticotropic Hormone↗
PubMed1992

The role of gender and taste class in the effects of stress on eating.

Participating in a laboratory study of the effects of stress on eating, healthy, nonsmoking men and women were shown a film about industrial accidents (stress condition) or a pleasant travelogue (control condition) and had access to sweet, salty, and bland snack food. Analyses of food consumption data revealed a significant interaction between sex of subject and the stress manipulation: Stress markedly and significantly decreased food consumption by men but resulted in some increased food consumption by women. Across the three food taste categories, men consistently ate less under stress than they did in the control condition. In contrast, women ate nearly twice as much sweet food and more bland food under stress than they did in the control condition, but these effects were not statistically significant. These results indicate that the relationship between stress and eating depends on the sex of the subject and may relate to type of food available. Contrasting generalizations about stress and eating reported in the archived literature can largely be reconciled by considering these interacting variables.

Adult↗
PubMed1992

National working conference on smoking and body weight. Task Force 1: Mechanisms relevant to the relations between cigarette smoking and body weight.

Careful, comprehensive, and empirical observations provide the building blocks of the sciences, whereas theory and mechanisms provide the "cement" to hold the blocks together and serve as blueprints to direct future building. This article resulted from several days of discussion regarding theories that may underlie the relation between cigarette smoking and body weight and the relation between smoking cessation and body weight. The working group composed of social and biological scientists who addressed this assignment considered what is already known within the smoking and body weight literature and also considered relevant findings from studies of smoking or body weight regulation that have not directly addressed the interaction of these variables. As expected, we were successful at listing some of what is not known and what is worth knowing. We also tried to identify fruitful possibilities for research activity that might clarify mechanisms of action and eventually lead to theoretical development. Because we do not believe that the present state of our deliberations merits the label of theories, we decided, instead, to report the summary of these deliberations as potential mechanisms relevant to the relation between smoking and body weight.

Adult↗
PubMed1991

Effects of nicotine on the acoustic startle reflex amplitude in rats.

The acoustic startle reflex was used to measure changes in sensorimotor reactivity in response to nicotine administration and cessation. Male rats received saline, 6 mg/kg/day or 12 mg/kg/day nicotine delivered subcutaneously by osmotic minipumps. The pumps delivered their contents during a 10-day period of implantation, after which time they were explanted. Animals were tested for startle reflex amplitudes using two levels of white noise bursts prior to pump implantation, on days 1 and 7 of nicotine or saline administration, and on several days following drug cessation. Nicotine produced a dose-dependent increase in startle amplitude during the period of administration that decreased during cessation. Results are interpreted in terms of nicotine's actions to enhance attentional processes.

Acoustic Stimulation↗
PubMed1991

Gender, stress, and health.

Studying men and women and differences between them has long been a goal for researchers in health psychology. Recent advances in this endeavor, reflected in this special issue on the topic, have led to important information about the relationships between health and behavior. Of particular interest are possible differences in psychophysiological response, stress, and immune function. Clearly, more inclusive research strategies hold great promise for future scientific discoveries.

Disease Susceptibility↗
PubMed1991

Conceptual and methodological considerations for tobacco addiction research.

The 1988 Surgeon General's Report on nicotine addiction has research and treatment implications. It focuses clinical treatments on tobacco use as an addiction and highlights the importance of examining actions of nicotine relevant to dependence. It also indicates the value of comparing the pharmacologic and behavioral processes underlying use of nicotine with other addictive drugs. This essay points out gaps that remain in our understanding of nicotine addiction. For example, the exact mechanisms underlying nicotine addiction are unknown. Also, the reasons for individual differences in initiation, withdrawal, relapse and reinforcing effects of tobacco use are not understood. Research designed to address these issues should be problem-driven and multidisciplinary. Parallel human and animal studies that include unconditioned as well as conditioned behaviors are particularly valuable.

Animals↗
PubMed1991

Gender differences in tobacco use.

Gender differences in overall tobacco use clearly exist. In general, men are more likely to use tobacco products than are women. However, this simple generalization, ignoring type of tobacco products, time, and culture, masks many more interesting gender differences in tobacco use. There are pronounced gender differences in tobacco use of specific tobacco products within some cultures but not others. Yet these differences have changed across time, including narrowing and widening of this gender gap, depending on culture and tobacco product. This article addresses these issues and presents possible psychosocial, biological, and psychobiological explanations for these phenomena. In addition, the implications of these differences and ways to learn more about these important differences are discussed.

Adult↗
PubMed1990

Effects of nicotine on body weight, food consumption and body composition in male rats.

The present study examined the effects of nicotine administration and cessation on body weight, food consumption, and body composition in rats. Administration of nicotine was associated with attenuated body weight gains and cessation was associated with accelerated body weight gains. Changes in fat composition paralleled changes in body weight, whereas changes in body water and protein did not. These results suggest that nicotine administration decreases body weight through its effects on fat stores in the body. After cessation of nicotine, body fat rapidly approached levels of control animals.

Adipose Tissue↗
PubMed1990

Variations in food preference and consumption across the menstrual cycle.

There is some evidence that food consumption changes across the menstrual cycle. However, archived studies tend to rely on self-report data and do not differentiate among types of food eaten. The present laboratory study was designed to measure women's taste preferences and specific food consumption across the menstrual cycle. Women came into the laboratory, consumed everyday foods, and rated them on taste judgment scales. The foods were weighed before and after the tasting session to determine amount eaten. After the tasting session, subjects completed several questionnaires (e.g., measures of affect, restrained eating, menstrual cycle and menstrual symptoms). Physical measurements (e.g., height, weight) were taken at the end of the session. Sweet food consumption and preference ratings were significantly higher during the premenstrual period. Consumption and ratings of other foods did not differ. There were no differences in levels of mood, obesity, or restrained eating across the menstrual cycle. Low restraint was associated with reporting fewer menstrual symptoms, in general, and slightly better mood. These results support the idea that specific taste preferences change over the menstrual cycle, and that endocrinological factors could be involved in this phenomenon.

Adult↗
PubMed1989

Smoking.

Explore the source record for details and available documents.

Forecasting↗