The purpose of the current experiment by Sarti et al. (2007) was to look at the way cocaine affects the structural and functional plasticity in neurons in the Ventral Tegmental Area (VTA) after acute cocaine administration. Electrophysiology, Voltage Clamp Techniques, and cell morphology was used to identify various cell types in the VTA. This allowed the researchers to further isolate which cells elicited increases in dendritic spine density as a result of acute cocaine administration. This study further helps understand the effects of cocaine on neuronal remodeling, as well as a possible mechanism for addictive behavior. The study also provides a better understanding of the results of cocaine on the brain. The VTA has been associated with
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Five VTA cells were put in Golgi-Cox fixative and processed, one type I and one type II cell from each the nuclei parabrachialis and paranigralis of the VTA, and one type I cell from midline group. Electrophysiological data was collected using picrotoxin to block GABAA receptor-mediated inhibitory post-synaptic currents. Ih was determined by using a voltage gate technique. To analyze VTA neuronal excitability, depolarizing currents were applied, and the slope of the number of spikes per depolarizing step was used. AMPA and NMDA receptors were also looked at as a ratio using voltage clamp to determine excitatory post synaptic currents (EPSC). The neurons were then filled with biocytin and stained with anti-TH antibodies, and analyzed for classification. The spine density was counted without the experimenter knowing the treatment groups. Cells were classified based on their previously known morphological and electrophysiological …show more content…
Type II neurons had medium cell bodies, stellate shaped, five primary dendrites, and did not exhibit thinning varicosities. Hyperpolarizing steps were done and they found that the subsequent Ih current sag, as well as leak channel function, was larger in the type II neurons in comparison to the type I neurons. When looking at intrinsic excitability, type I neurons spiked more often than the type II neurons over the depolarizing steps. A slow wave oscillation firing was also observed in only the type II neurons. These measures allowed for the conclusion that type I and type II cells in the VTA can be categorized based on electrophysiological
Five VTA cells were put in Golgi-Cox fixative and processed, one type I and one type II cell from each the nuclei parabrachialis and paranigralis of the VTA, and one type I cell from midline group. Electrophysiological data was collected using picrotoxin to block GABAA receptor-mediated inhibitory post-synaptic currents. Ih was determined by using a voltage gate technique. To analyze VTA neuronal excitability, depolarizing currents were applied, and the slope of the number of spikes per depolarizing step was used. AMPA and NMDA receptors were also looked at as a ratio using voltage clamp to determine excitatory post synaptic currents (EPSC). The neurons were then filled with biocytin and stained with anti-TH antibodies, and analyzed for classification. The spine density was counted without the experimenter knowing the treatment groups. Cells were classified based on their previously known morphological and electrophysiological …show more content…
Type II neurons had medium cell bodies, stellate shaped, five primary dendrites, and did not exhibit thinning varicosities. Hyperpolarizing steps were done and they found that the subsequent Ih current sag, as well as leak channel function, was larger in the type II neurons in comparison to the type I neurons. When looking at intrinsic excitability, type I neurons spiked more often than the type II neurons over the depolarizing steps. A slow wave oscillation firing was also observed in only the type II neurons. These measures allowed for the conclusion that type I and type II cells in the VTA can be categorized based on electrophysiological