Acute in vivo nicotine administration enhances synchrony among dopamine neurons |
| |
Authors: | Li Wei Doyon William M Dani John A |
| |
Institution: | aCenter on Addiction, Learning, Memory, Department of Neuroscience, Menninger Department of Psychiatry and Behavioral Sciences, Baylor College of Medicine, Houston, TX 77030, United States;bDiana Helis Henry Medical Research Foundation, New Orleans, LA 70130, United States |
| |
Abstract: | Altered functional interactions among midbrain dopamine (DA) neurons contribute to the reinforcing properties of environmental stimuli and addictive drugs. To examine correlations among DA neurons, acute nicotine was administrated to rats via an intraperitoneal catheter and unit activity was measured using multi-tetrode in vivo recordings. Nicotine administration enhanced the correlated activity of simultaneously recorded DA neurons from the ventral tegmental area (VTA). The strength of the correlations between DA neuron pairs, as measured by cross covariance among two spike trains, showed dynamic changes over time. Nicotine produced a gradual rise in firing rate and burst activity that reached a stable plateau approximately 20 min after the intraperitoneal nicotine infusion. Shortly after that time the cross correlations measured using 5-ms bins increased significantly above baseline. In addition, nicotine increased the firing rates of DA neurons in the posterior VTA more than in the anterior VTA. Unlike nicotine, eticlopride administration also boosted DA neuron firing activity but did not enhance synchronization, indicating that the cross correlations induced by nicotine were not due to a non-specific increase in firing rate. The overall results show that nicotine induces nearly synchronous firing by a subset of DA neurons, and those changes in correlative firing will enhance the DA signal that contributes to nicotine-induced behavioral reinforcement. |
| |
Keywords: | Abbreviations: ACh acetylcholine DHβE dihydro-β-erythroidine DA dopamine ISI interspike interval nAChR nicotinic acetylcholine receptor NAc nucleus accumbens SNc substantia nigra compacta VTA ventral tegmental area |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|