The activation of 5-HT(3) receptors evokes GABA release in the spinal cord.
We carried out experiments using a microdialysis method to determine whether activation of 5-HT(3) receptors increases the concentration of GABA in the dorsal horn of the spinal cord. Intrathecal perfusion of a selective 5-HT(3) receptor agonist, 1-phenylbiguanide (0.3, 1.0, and 3.0 mM) dose-dependently, increased GABA concentration, while concentrations of glutamate and glycine were not changed. The concentration of aspartate was increased only by 3.0 mM of 1-phenylbiguanide. Our results have provided direct evidence that activation of 5-HT(3) receptors evokes GABA release in the spinal dorsal horn, possibly producing analgesia.
Kawamata
Tomoyuki
T
Department of Anesthesiology, Sapporo Medical University School of Medicine, South 1, West 16, Chuo-ku, Sapporo, Hokkaido 060-8543, Japan. kawamata@sapmed.ac.jp
Omote
Keiichi
K
Toriyabe
Masaki
M
Yamamoto
Hiroki
H
Namiki
Akiyoshi
A
D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001645:Biguanides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D008297:Male; D017551:Microdialysis / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000378:metabolism*; D044406:Receptors, Serotonin, 5-HT3; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D013116:Spinal Cord / Q000033:anatomy & histology / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D001645:Biguanides; D011985:Receptors, Serotonin; D044406:Receptors, Serotonin, 5-HT3; D017366:Serotonin Receptor Agonists; D001224:Aspartic Acid; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D005998:Glycine; C008846:phenyl biguanide