Neurons in the pressor sites of dorsal and ventrolateral medulla mediate pressor actions of the periaqueductal grey of midbrain.
In 14 cats anesthetized with chloralose (40 mg/kg) and urethane (400 mg/kg) the pressor area in the ventrolateral periaqueductal grey (PAG) of midbrain was activated by rectangular pulses. The induced increases of systemic arterial pressure (SAP) and plasma norepinephrine (NE) and epinephrine (EPi) were compared before and after destructing portion of cell bodies (sparing passing fibers) in the pressor sites of dorsal (DM) and rostral ventrolateral medulla (VLM) by microinjection of kainic acid. Destruction on VLM or DM reduced the PAG-induced pressor responses and increases in plasma NE and EPi. The reduction of pressor responses, however, was more predominant following VLM than DM destruction. On the other hand, the decrease in plasma NE, was slightly more apparent following DM than VLM destruction.
Chai
C Y
CY
Institute of Biomedical Sciences, Academia Sinica, Department of Biology, Taipei, Taiwan R.O.C.
Yuan
C
C
Horng
H T
HT
Wang
S D
SD
Tseng
C J
CJ
Kuo
J S
JS
D000818:Animals; D001794:Blood Pressure; D002415:Cats; D004837:Epinephrine / Q000097:blood; D005260:Female; D006339:Heart Rate; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D009638:Norepinephrine / Q000097:blood; D010487:Periaqueductal Gray / Q000502:physiology*
D009638:Norepinephrine; D004837:Epinephrine