[Effect of endothelin-1 injected into rostral ventrolateral medulla on cardiovascular responses in cats].
OBJECTIVE
To study the effect of endothelin-1 (ET-1) in the rostral ventrolateral medulla (rVLM) on cardiovascular responses in cats.


METHODS
The stereotatic technique and microinjection method were used.


RESULTS
ET-1 (4 mumol.L-1 0.5 microL) microinjected into rVLM induced mean arterial pressure (MAP) increasing (3.7 +/- 1.3) kPa, heart rate (HR) accelerating (29 +/- 7) beats.min-1, and renal nerve activity (RNA) intensifying 45% +/- 10%. The effects were dose-dependent. Before and after bilateral vagotomy, there was no significant difference in the reaction of MAP, HR, and RNA. After intravenous injection with phentolamine (5 mg.kg-1, alpha-blocker), ET-1 did not induce significant change of MAP. ET-1 raised the content of peripheral plasma argipressin (Arg) from (12.4 +/- 6.5) to (70.3 +/- 24.2) ng.L-1 with radioimmunoassay, and showed a correlation with MAP changes. ET-1 induced heart rhythm disorder (HRhD) in acute myocardiac ischemia, the occur time of HRhD was (4.8 +/- 2.9) min, and the score was 4.4 +/- 1.6, and it was significantly different from control.


CONCLUSIONS
ET-1 microinjected into rVLM could involve with control regulation of cardiovascular and sympathetic nerve activity.
Yang
X L
XL
Department of Physiology, School of Basic Medicine, Second Military Medical University, Shanghai, China.
Fu
W J
WJ
Hou
G X
GX
Chen
J G
JG
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002415:Cats; D019332:Endothelin-1 / Q000009:adverse effects / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology*; D008845:Microinjections; D010646:Phentolamine / Q000494:pharmacology; D013564:Sympathetic Nervous System / Q000187:drug effects; D013565:Sympatholytics / Q000494:pharmacology; D014628:Vagotomy
D019332:Endothelin-1; D013565:Sympatholytics; D010646:Phentolamine