Effect of serotonin (5-HT) on trigeminal rhythmic activities generated in in vitro brainstem block preparations.
We used rat isolated brainstem block preparations to analyze the functional roles of serotonin receptors in the generation of trigeminal rhythmic activities. We previously reported that trigeminal rhythmic activities could be induced by some pharmacological applications in an isolated brainstem preparation with a rostral boundary at the border between the inferior and superior colliculus, and a caudal border at the level of the rostral facial nucleus. However, the same stimulation did not induce trigeminal rhythmic activities in a whole brainstem block preparation with the same rostral boundary and a caudal border at the obex level. In the present study, both the 5-HT(1A) phthalimido-butyl-piperazine, and the 5-HT(2C) agonist, 1-2,5-dimethoxy-4-iodophenyl-2-aminopropane, combined with N-methyl-D,L-aspartate and bicuculline, elicited trigeminal rhythmic activities in a whole brainstem block preparation. Our results suggest that serotonin has both facilitation and inhibition effects on the generation of trigeminal rhythmic activities in an isolated brainstem block preparation in vitro.
First Department of Oral & Maxillofacial Surgery, Osaka University, Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Japan.
A
A
Mori
M
M
Kogo
K
K
Ishihama
S
S
Tanaka
A
A
Enomoto
H
H
Koizumi
T
T
Matsuya
D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000494:pharmacology; D001933:Brain Stem / Q000187:drug effects*; D004566:Electrodes; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D020546:Fourth Ventricle / Q000187:drug effects; D018756:GABA Antagonists / Q000494:pharmacology; D007215:Indophenol / Q000031:analogs & derivatives* / Q000494:pharmacology; D007245:Inferior Colliculi / Q000187:drug effects; D008784:Methysergide / Q000494:pharmacology; D009046:Motor Neurons / Q000187:drug effects; D016202:N-Methylaspartate / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects; D010879:Piperazines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology; D012815:Signal Processing, Computer-Assisted; D013223:Statistics as Topic; D013477:Superior Colliculi / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects; D014276:Trigeminal Nerve / Q000187:drug effects*; D014278:Trigeminal Nuclei / Q000187:drug effects*
D018690:Excitatory Amino Acid Agonists; D018756:GABA Antagonists; D010879:Piperazines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D017366:Serotonin Receptor Agonists; C113896:dimethoxy-4-indophenyl-2-aminopropane; C058895:1-(2-methoxyphenyl)-4-(4-(2-phthalimido)butyl)piperazine; D012701:Serotonin; D007215:Indophenol; D016202:N-Methylaspartate; D008784:Methysergide; D001640:Bicuculline