Neuroscience 2002 Abstract
| Presentation Number: | 636.7 |
|---|---|
| Abstract Title: | SEROTONIN-INDUCED REDUCTION OF H-CURRENT IN VENTRAL TEGMENTAL AREA DOPAMINE NEURONS IS MEDIATED BY 5-HT<sub>2</sub> RECEPTORS. |
| Authors: |
Bunney, E. B.*1
; Appel, S. B.2
; Brodie, M. S.2
1Emergency Medicine, University of Illinois at Chicago, Chicago, IL 2Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL |
| Primary Theme and Topics |
Synaptic Transmission and Excitability - Neurotransmitters -- Serotonin |
| Session: |
636. Neurotransmitters: serotonin--physiology Poster |
| Presentation Time: | Wednesday, November 6, 2002 10:00 AM-11:00 AM |
| Location: | Hall A2-B3 C-33 |
| Keywords: | SEROTONIN RECEPTOR, DOPAMINERGIC, BRAIN SLICE, PATCH CLAMP |
Dopaminergic (DA) neurons in the ventral tegmental area (VTA) have the hyperpolarization activated cationic current (Ih) and receive serotonergic innervation from the raphe nuclei. We have previously shown that serotonin (5-HT, 50 - 500 µM) reduces the amplitude of Ih in a concentration-dependent manner (Liu et al. SFN Abstr. 25:439, 1999). In the present study, whole cell patch-in-the-slice recording from DA VTA neurons was used to measure Ih under voltage clamp conditions. Ih was evoked by hyperpolarizing voltage steps (duration 1 sec) from a holding potential of -60 mV to -130 mV (in 10 mV increments) and Current/Voltage (Ih/V) curves were constructed. Drug-induced changes in Ih were evaluated from Ih/V curves measured in control and in the presence of each drug, in the same VTA neuron. Bath application of the 5-HT2 receptor agonist α-methylserotonin (α-Me5-HT, 25 µM) reduced Ih over the entire voltage range in all 8 neurons tested. The mean percent reduction in Ih measured at -120 mV was -19.7 ± 2.8%, n=8. The reduction in Ih by α-Me5-HT was statistically significant (paired t-test, p<0.001, n=8) and was reversible with washout (n=3). The reduction of Ih by α-Me5-HT was completely reversed by adding the selective 5-HT2 receptor antagonist ketanserin (25 µM, n=3). These data indicate that the 5-HT-induced reduction of Ih is mediated by 5-HT2 receptors. As 5-HT2 receptors are coupled to the phospholipase C cascade, the present data are consistent with our recent observation that the 5-HT-induced decrease in Ih is mediated by protein kinase C (Liu et al., submitted).
Supported by PHS Grants: DA00285 (E.B.B.) and AA09125 (M.S.B.)
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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