Journal article
Possible involvement of neuronal nitric oxide synthase enzyme in early-phase isoflurane-induced hypotension in rats
Life sciences (1973), Vol.76(5), pp.499-507
2004
Handle:
https://hdl.handle.net/2376/115525
PMID: 15556163
Abstract
This study was conducted to demonstrate the involvement of nitric oxide synthase (NOS) in the early-phase isoflurane-induced hypotension and to ascertain whether this NOS is neuronal NOS (nNOS) or endothelial NOS (eNOS). Mean arterial pressures (MAPs) were directly measured from the femoral arteries of urethane-anesthetized rats. Isoflurane-induced changes in MAP were monitored in rats following pretreatment with vehicle or one of the following NOS inhibitors: L-N
G-monomethyl-L-arginine (L-NMMA), which is non-selective; L-N
G-nitro arginine (L-NOARG), which is more selective for nNOS and eNOS; and 7-nitroindazole (7-NI), which is selective for nNOS. Exposure to 2% isoflurane in oxygen produced a triphasic reduction in MAP, including an early phase in which mean arterial pressure (MAP) fell by 25-30% during the initial 2½ min. This early hypotensive response, but not subsequent phases, was abolished by i.v. pretreatment with either L-NMMA or L-NOARG. The early-phase hypotension was also significantly attenuated by i.p. pretreatment with 7-NI; however, the blockade was not as complete as with L-NMMA or L-NOARG. Cerebella and aorta were removed from vehicle- and 7-NI pretreated rats and assayed for NOS activity by determining the conversion of [
14C]L-arginine to [
14C]L-citrulline. The 7-NI pretreatment significantly reduced NOS activity in the cerebellum but not the aorta. These findings indicate that the early-phase isoflurane-induced hypotension may involve nNOS as well as eNOS. The nNOS may participate in regulation of isoflurane-induced neuronal release of endogenous opioid peptide, which produces a vasodilation that is dependent on NO derived from an action of eNOS.
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Details
- Title
- Possible involvement of neuronal nitric oxide synthase enzyme in early-phase isoflurane-induced hypotension in rats
- Creators
- Elizabeth A Ellenberger - Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, Illinois, USAHeather L Lucas - Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, Illinois, USAJanet L Mueller - Department of Biomedical Sciences, University of Illinois College of Medicine at Rockford, Rockford, Illinois, USAPeggy L BarringtonEunhee Chung - Department of Pharmaceutical Sciences, College of Pharmacy, USAYusuke Ohgami - Department of Pharmaceutical Sciences, College of Pharmacy, USARaymond M Quock - Department of Pharmaceutical Sciences, College of Pharmacy, USA
- Publication Details
- Life sciences (1973), Vol.76(5), pp.499-507
- Academic Unit
- Psychology, Department of
- Publisher
- Elsevier Inc
- Identifiers
- 99900547553801842
- Language
- English
- Resource Type
- Journal article