Local GABAergic modulation of the activity of serotoninergic neurons in the nucleus raphe magnus.
Experiments on rat brainstem sections in membrane potential clamping conditions addressed the effects of serotonin and GABA on serotoninergic neurons in the nucleus raphe magnus. Local application of serotonin stimulated inhibitory postsynaptic currents (IPSC) in 45% of the serotoninergic neurons studied. This response was not seen in the presence of the fast sodium channel blocker tetrodotoxin. The GABAA receptor antagonist gabazine blocked IPSC in both serotonin-sensitive and serotonin-insensitive neurons. Application of GABA evoked generation of a membrane current (IGABA), which was completely blocked by gabazine. These results indicate self-regulation of the activity of serotoninergic neurons in the nucleus raphe magnus via a negative feedback circuit involving local GABAergic interneurons.
Inyushkin
A N
AN
Samara State University, 1 Academician Pavlov Street, 443016, Samara, Russia. ainyushkin@hotmail.com
Merkulova
N A
NA
Orlova
A O
AO
Inyushkina
E M
EM
D000818:Animals; D025461:Feedback, Physiological; D058787:GABA-A Receptor Antagonists / Q000494:pharmacology; D015640:Ion Channel Gating; D008297:Male; D008564:Membrane Potentials; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D011724:Pyridazines / Q000494:pharmacology; D011903:Raphe Nuclei / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000494:pharmacology / Q000502:physiology*; D015222:Sodium Channels; D013779:Tetrodotoxin / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology / Q000502:physiology*
D058787:GABA-A Receptor Antagonists; D011724:Pyridazines; D015222:Sodium Channels; D012701:Serotonin; D013779:Tetrodotoxin; D005680:gamma-Aminobutyric Acid; C049853:gabazine