Inhibitory Modulation of 5-Hydroxytryptamine on Corticostriatal Synaptic Transmission in Rat Brain Slice.
- Author:
Se Joon CHOI
1
;
Won Soon CHUNG
;
Ki Jung KIM
;
Ki Wug SUNG
Author Information
1. Department of Pharmacology, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea. sungkw@cmc.cuk.ac.kr
- Publication Type:In Vitro ; Original Article
- Keywords:
Striatum;
5-Hydroxytryptamine;
Population spike;
Synaptic transmission;
Depression
- MeSH:
Animals;
Baths;
Brain*;
Cerebral Cortex;
Corpus Callosum;
Depression;
Glutamic Acid;
Learning;
N-Methylaspartate;
Neurotransmitter Agents;
Raphe Nuclei;
Rats*;
Receptors, Glutamate;
Receptors, N-Methyl-D-Aspartate;
Serotonin*;
Synapses;
Synaptic Transmission*
- From:The Korean Journal of Physiology and Pharmacology
2003;7(6):295-301
- CountryRepublic of Korea
- Language:English
-
Abstract:
Striatum plays a crucial role in the movement control and habitual learning. It receives an information from wide area of cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from raphe nuclei. In the present study, the effects of 5-HT to modulate synaptic transmission were studied in the rat corticostriatal brain slice using in vitro extracellular recording technique. Synaptic responses were evoked by stimulation of cortical glutamatergic inputs on the corpus callosum and recorded in the dorsal striatum. 5-HT reversibly inhibited coticostriatal glutamatergic synaptic transmission in a dose-dependent fashion (5, 10, 50, and 100 microM), maximally reducing in the corticostriatal population spike (PS) amplitude to 40.1+/-5.0% at a concentration of 50 microM 5-HT. PSs mediated by non-NMDA glutamate receptors, which were isolated by bath application of the NMDA receptor antagonist, d, l-2-amino-5-phospohonovaleric acid (AP-V), were decreased by application of 50 microM 5-HT. However, PSs mediated by NMDA receptors, that were activated by application of zero Mg2+ aCSF, were not significantly affected by 50 microM 5-HT. To test whether the corticostriatal synaptic inhibitions by 5-HT might involve a change in the probability of neurotransmitter release from presynaptic nerve terminals, we measured the paired-pulse ratio (PPR) evoked by 2 identical pulses (50 ms interpulse interval), and found that PPR was increased (33.4+/-5.2%) by 5-HT, reflecting decreased neurotransmitter releasing probability. These results suggest that 5-HT may decrease neurotransmitter release probability of glutamatergic corticostriatal synapse and may be able to selectively decrease non-NMDA glutamate receptor-mediated synaptic transmission.
