JOURNAL OF OSAKA DENTAL UNIVERSITY

Vol. 41 No. 2      OCTOBER - 2007

ISSN: 0475-2058      UBIC: 172

SUMMARY

Many anesthetics influence intracranial environmental factors such as cerebral blood flow (CBF). Although it has been reported that CBF is closely associated with general an- esthetics and nitric oxide (NO), no study has investigated the link between NO and cerebrospinal fluid (CSF) circulation. To examine this issue, we conducted a CSF quantification experiment in six adult cats by the ventriculo-cisternal perfusion (VCP) method using a nitric oxide synthase (NOS) inhibitor, NG-nitro-L-arginine methyl ester (L-NAME). Continuous mean arterial pressure (MAP) was monitored throughout the experiment. We administered VCP to see how it affected CSF circulation. Regional CBF (r-CBF) was measured with a laser blood flow meter. We calculated CSF production and absorption based on Vf (the rate of CSF formation) and Va (the rate of CSF reabsorption). To investigate the influence of NO, we administered L-NAME at 30 mg/kg as a single dose followed by infusion at the rate of 1 mg/kg/min. We found that L-NAME administration significantly increased MAP. However, there were no changes in r-CBF. L-NAME administration did not affect Vf or Va. Although the acute inhibition of NOS by L-NAME increased MAP, it did not influence the circulatory kinetics of either CSF or r-CBF. However, the decrease in blood flow in the choroid plexus, as reported by Faraci et al., was not consistent with the homeostasis of CSF production. (J Osaka Dent Univ 2007 ; 41 : 137-142) Key words: Cerebrospinal fluid; Nitric oxide; Circulation; L-NAME.

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