Rats trained to lever-press for electrical stimulation of the nucleus accumbens, lateral hypothalamus, or ventral tegmental area, were tested with a range of stimulation frequencies to assess the effects of naltrexone (2.5, 5.0, 10.0, 20.0 mg/kg, i.p.) during sessions beginning 15 or 45 min after injection. Naltrexone, when effective, shifted the rate-frequency functions to the right; the magnitude of the effect depended on site of stimulation and on the delay after injection. The greatest effect was observed with stimulation of the nucleus accumbens and the least with stimulation of the ventral tegmental area. There was a greater attenuation of responding during the late test sessions than during the early ones. The time course of naltrexone's effect on brain stimulation reward was determined for the highest dose by measuring a rat's rate of responding over a 3 h period in sessions with immediate access (5-min delay) or delayed access (45-min delay) to stimulation. The greatest decreases in responding were observed 45, 65, and 85 min after injection and the delay in access made little difference. The fact that the drug was more effective 45 min after injection explains some of the inconsistencies in the literature; the fact that its effectiveness was independent of early exposure to stimulation would suggest pharmacological rather than experiential factors as the explanation of the delayed effectiveness.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/0006-8993(88)90594-x | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Ventral hippocampus to nucleus accumbens shell circuit regulates approach decisions during motivational conflict.
PLoS Biol
January 2025
Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.
Successful resolution of approach-avoidance conflict (AAC) is fundamentally important for survival, and its dysregulation is a hallmark of many neuropsychiatric disorders, and yet the underlying neural circuit mechanisms are not well elucidated. Converging human and animal research has implicated the anterior/ventral hippocampus (vHPC) as a key node in arbitrating AAC in a region-specific manner. In this study, we sought to target the vHPC CA1 projection pathway to the nucleus accumbens (NAc) to delineate its contribution to AAC decision-making, particularly in the arbitration of learned reward and punishment signals, as well as innate signals.
View Article and Find Full Text PDFThe Comorbidity of Depression and Diabetes Is Involved in the Decidual Protein Induced by Progesterone 1 (Depp1) Dysfunction in the Medial Prefrontal Cortex.
Metabolites
January 2025
Jiangsu Provincial Key Laboratory of Drug Metabolism and Pharmacokinetics, State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China.
Background: There is a high rate of depressive symptoms such as irritability, anhedonia, fatigue, and hypersomnia in patients with type 2 diabetes mellitus (T2DM). However, the causes and underlying mechanisms of the comorbidity of depression and diabetes remain unknown.
Methods: For the first time, we identified Decidual protein induced by progesterone 1 (Depp1), also known as DEPP autophagy regulator 1, as a hub gene in both depression and T2DM models.
Impact of Exercise on Tramadol-Conditioned Place Preference.
Brain Sci
January 2025
Department of Biological Sciences, Faculty of Science, Yarmouk University, Irbid 21163, Jordan.
Background: Tramadol (TRA) is an opioid that is used to manage moderate to severe pain. Long-term use of TRA can lead to the development of opioid use disorder.
Objectives: This study investigates the role of forced exercise in reducing TRA-seeking behavior.
Role of Hypothalamus in Acupuncture's Effects.
Brain Sci
January 2025
Department of Physiology, College of Medicine, Yonsei University, Seoul 03722, Republic of Korea.
The significant correlation between ancient medicinal practices and brain function marks a revolutionary frontier in the field of neuroscience. Acupuncture, a traditional oriental medicine, can affect brain regions, such as the hypothalamus, anterior cingulate, posterior cingulate, and hippocampus, and produces specific therapeutic effects, such as pain relief, suppression of hypertension, and alleviation of drug addiction. Among the brain regions, the hypothalamus, a small yet critical region in the brain, plays a pivotal role in maintaining homeostasis by regulating a wide array of physiological processes, including stress responses, energy balance, and pain modulation.
View Article and Find Full Text PDFIdentification of the subventricular tegmental nucleus as brainstem reward center.
Science
January 2025
Laboratory of Cerebral Cortex Research, HUN-REN Institute of Experimental Medicine, Budapest, Hungary.
Rewards are essential for motivation, decision-making, memory, and mental health. We identified the subventricular tegmental nucleus (SVTg) as a brainstem reward center. In mice, reward and its prediction activate the SVTg, and SVTg stimulation leads to place preference, reduced anxiety, and accumbal dopamine release.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!