Effects of isoflurane on brain stem blood flow and renal sympathetic nerve activity during induced hypotension.
Effects of isoflurane on arterial blood pressure, regional blood flow in the brain stem, and renal sympathetic nerve activity were compared with those during vasodilator-induced hypotension using decerebrate unanesthetized cats. Either prostaglandin E1 (PGE1) or trinitroglycerin (TNG) was used to decrease the mean arterial pressure 30% below the control level. The effects of isoflurane (0.5 MAC for 15 min) were examined in the following three conditions: (1) during PGE1-induced hypotension; (2) during TNG-induced hypotension, and (3) without either vasodilator. Isoflurane decreased the brain stem blood flow in parallel with a systemic blood pressure fall. Electrical activity of the renal sympathetic nerve consisted of a high-amplitude phasic and a low-amplitude tonic discharge. Isoflurane decreased the phasic activity and increased the tonic activity. Although the two vasodilators had a similar effect on systemic blood pressure and renal sympathetic discharge, TNG decreased the brain stem blood flow to a lesser extent than PGE1. However, the effects of isoflurane on all parameters were statistically identical in the three conditions not treated and pretreated with either vasodilator. Also, the blood concentrations of isoflurane did not differ among the three conditions. The present study demonstrates that isoflurane produces similar effects on systemic blood pressure, regional cerebral blood flow and sympathetic efferent discharge during vasodilator-induced hypotension and without any vasodilator.
Kiriyama
M
M
Department of Anesthesiology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, Japan.
Haji
A
A
Masuda
A
A
Ito
Y
Y
Takeda
R
R
D000527:Alprostadil / Q000008:administration & dosage / Q000494:pharmacology; D000704:Analysis of Variance; D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001933:Brain Stem / Q000098:blood supply* / Q000187:drug effects; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D003655:Decerebrate State; D004558:Electric Stimulation; D005260:Female; D007022:Hypotension / Q000139:chemically induced / Q000503:physiopathology*; D007530:Isoflurane / Q000008:administration & dosage / Q000097:blood / Q000378:metabolism / Q000494:pharmacology*; D007668:Kidney / Q000187:drug effects / Q000294:innervation* / Q000503:physiopathology; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000473:pathology; D005996:Nitroglycerin / Q000008:administration & dosage / Q000494:pharmacology; D013223:Statistics as Topic; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000503:physiopathology; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000494:pharmacology
D018685:Anesthetics, Inhalation; D014665:Vasodilator Agents; D007530:Isoflurane; D000527:Alprostadil; D005996:Nitroglycerin