[Inhibitory effect of diazepam or flurazepam on pressor response induced by the stimulation of midbrain in the rabbit].
Experiments were performed on 32 rabbits anaesthetized with alpha-chloralose and urethane, paralyzed with flaxidil and artificially ventilated. The pressor response was elicited by stimulation of dorsal part of midbrain periaqueductal gray (dPAG). Intravenous injection of diazepam (2 mg/kg) or intracerebroventricular application of flurazepam (2 mg/50 microliters) resulted in attenuation of the pressor response induced by the stimulation of midbrain. Bilateral microinjection of flurazepam (100 micrograms in 0.25 microliter) into rostral ventrolateral medulla (rVLM) depressed the pressor response to midbrain stimulation. Microinjection of flurazepam of the same dosage into caudal ventrolateral medulla (cVLM), however, had no depressant effect. Pretreatment with bicuculline in rVLM prevented the inhibitory effect of flurazepam on the pressor response. These results mentioned above suggest that diazepam or flurazepam inhibits the pressor response evoked by midbrain stimulation, and the effect may be mediated by the activation of the GABAA receptor in rVLM.
Xu
N S
NS
Department of Physiology, Shanghai Medical University.
Guo
X Q
XQ
Zhang
J R
JR
D000818:Animals; D001794:Blood Pressure; D003975:Diazepam / Q000494:pharmacology*; D005479:Flurazepam / Q000494:pharmacology*; D006339:Heart Rate; D008526:Medulla Oblongata / Q000502:physiology; D008636:Mesencephalon / Q000502:physiology*; D011311:Pressoreceptors / Q000502:physiology; D011817:Rabbits
D005479:Flurazepam; D003975:Diazepam