[Nucleus fastigius-rostral ventrolateral medulla system is involved in vestibular depressor and bradycardia responses].
In urethane-anesthetized, tubocurarine-immobilized and artificially ventilated rats, microinjection of L-glutamate (Glu) into the nucleus fastigius or nucleus vestibular superior caused a depressor and bradycardia response. Both the depressor and bradycardia responses of the nucleus fastigius and nucleus vestibularis superior were blocked by preinjection of bicuculline (a GABAergic receptor blocker) into the rostral ventrolateral medulla. And the cardiovascular response-induced by excitation of the nucleus vestibularis superior could also be blocked by procaine-injection into the nucleus fastigius. These results indicate that the vestibular depressor and bradycardia response was induced via the nucleus fastigius rostral ventrolateral medulla system. Intravenous injection of methyl atropine also markedly attenuated the cardiovascular response of the nucleus fastigius, indicating that the vagus nerve is also involved in the depressor and bradycardia response of vestibulo-fastigial excitation.
Luo
P
P
Department of Physiology, Beijing Medical University.
Gu
Y H
YH
D000818:Animals; D001286:Atropine Derivatives / Q000494:pharmacology; D001640:Bicuculline / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D005971:Glutamates / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects*; D008526:Medulla Oblongata / Q000502:physiology*; D008845:Microinjections; D010276:Parasympatholytics / Q000494:pharmacology; D051381:Rats; D014726:Vestibular Nuclei / Q000502:physiology*
D001286:Atropine Derivatives; D005971:Glutamates; D010276:Parasympatholytics; C006649:methylatropine; D001640:Bicuculline