Journal of Neurophysiology, Vol 62, Issue 2 481-486, Copyright © 1989 by APS

ARTICLES

5-HT-mediated synaptic potentials in the dorsal raphe nucleus: interactions with excitatory amino acid and GABA neurotransmission

Z. Z. Pan, W. F. Colmers and J. T. Williams
Vollum Institute for Advanced Biomedical Research, Oregon Health Science University, Portland 97201.

1. Intracellular recordings from neurons within dorsal raphe nucleus in slices from rat brain were used to study an inhibitory postsynaptic potential (IPSP) evoked by electrical stimulation. 2. The IPSP was observed in approximately 70% of neurons, had a latency to onset of 40-65 ms, reached a peak in 350-400 ms, had a total duration of 1-2 s, and reversed polarity at the potassium equilibrium potential. 3. This IPSP was blocked by spiperone (1 microM) and prolonged by fluoxetine (300 nM-30 microM) suggesting that it was mediated by 5-hydroxytryptamine (5-HT). 4. Superfusion with gamma-aminobutyric acid (GABA) and excitatory amino acid receptor antagonists were used to block "fast" synaptic potentials that preceded the IPSP such that it could be studied in isolation. Blockade of the GABA-mediated synaptic potentials increased the amplitude of the IPSP by 1.3-fold. The amplitude of the IPSP was reduced by 30% after blockade of the excitatory amino acid-mediated synaptic potential. 5. The results indicate that the IPSP recorded in dorsal raphe neurons was caused by 5-HT released at least in part from indirect (synaptically induced) excitation of 5-HT-containing cells within the slice.

This article has been cited by other articles:

				G. A. Carrasco, K. J. Damjanoska, D. N. D'Souza, Y. Zhang, F. Garcia, G. Battaglia, N. A. Muma, and L. D. Van de Kar Short-Term Cocaine Treatment Causes Neuroadaptive Changes in G{alpha}q and G{alpha}11 Proteins in Rats Undergoing Withdrawal J. Pharmacol. Exp. Ther., October 1, 2004; 311(1): 349 - 355. [Abstract] [Full Text] [PDF]

				M. K.-H. Schafer, H. Varoqui, N. Defamie, E. Weihe, and J. D. Erickson Molecular Cloning and Functional Identification of Mouse Vesicular Glutamate Transporter 3 and Its Expression in Subsets of Novel Excitatory Neurons J. Biol. Chem., December 20, 2002; 277(52): 50734 - 50748. [Abstract] [Full Text] [PDF]

				H. Morikawa, O. J. Manzoni, J. C. Crabbe, and J. T. Williams Regulation of Central Synaptic Transmission by 5-HT1B Auto- and Heteroreceptors Mol. Pharmacol., April 13, 2001; 58(6): 1271 - 1278. [Abstract] [Full Text]

				M. F. Schmidt and D. J. Perkel Slow Synaptic Inhibition in Nucleus HVc of the Adult Zebra Finch J. Neurosci., February 1, 1998; 18(3): 895 - 904. [Abstract] [Full Text] [PDF]

				S. Ingram, T. J. Wilding, E. W. McCleskey, and J. T. Williams Efficacy and Kinetics of Opioid Action on Acutely Dissociated Neurons Mol. Pharmacol., July 1, 1997; 52(1): 136 - 143. [Abstract] [Full Text]

				D. A. Bayliss, Y.-W. Li, and E. M. Talley Effects of Serotonin on Caudal Raphe Neurons: Activation of an Inwardly Rectifying Potassium Conductance J Neurophysiol, March 1, 1997; 77(3): 1349 - 1361. [Abstract] [Full Text] [PDF]