Different tonic regulation of neuronal activity in the rat dorsal raphe and medial prefrontal cortex via 5-HT(1A) receptors.
It has been established that 5-HT(1A) receptors are expressed both presynaptically as autoreceptors by 5-HT containing neurones, and postsynaptically by a variety of other neurones. Activation of either somatodendritic 5-HT(1A) autoreceptors or postsynaptic 5-HT(1A) receptors induces hyperpolarisation and inhibition of action potential discharge of the neurones, but it is unclear whether 5-HT(1A) receptors are under a general tonic influence by 5-HT. In the present study, using single unit recordings from both anesthetized and non-anesthetized rats, we show that the activity of neurones in the medial prefrontal cortex is not altered by systemic administration of the selective 5-HT(1A) receptor antagonist, WAY 100635. In contrast, WAY 100635 increased the firing rate of 5-HT neurones in the dorsal raphe nucleus. Our findings indicate a tonic activation of presynaptic somatodendritic but not postsynaptic cortical 5-HT(1A) receptors.
Hajós
M
M
Oxford University Department of Clinical Pharmacology, Radcliffe Infirmary, Woodstock Road, Oxford OX2 6HE, UK. mihaly.hajos@am.pnu.com
Hoffmann
W E
WE
Tetko
I V
IV
Hyland
B
B
Sharp
T
T
Villa
A E
AE
D000818:Animals; D004594:Electrophysiology; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D010879:Piperazines / Q000494:pharmacology; D017397:Prefrontal Cortex / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011725:Pyridines / Q000494:pharmacology; D011903:Raphe Nuclei / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology*; D044263:Receptors, Serotonin, 5-HT1; D012702:Serotonin Antagonists / Q000494:pharmacology
D010879:Piperazines; D011725:Pyridines; D011985:Receptors, Serotonin; D044263:Receptors, Serotonin, 5-HT1; D012702:Serotonin Antagonists; C090413:N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl)cyclohexanecarboxamide