Effect of benzodiazepine hypnotic triazolam on relationship of blood pressure and Paco2 to cerebral blood flow during human non-rapid eye movement sleep.
We sought to clarify the effect of short-acting benzodiazepine hypnotic on the relationship of arterial blood pressure and arterial partial pressure of carbon dioxide (Paco2) to regional cerebral blood flow (rCBF) during human non-rapid-eye-movement (non-REM) sleep. Nine young normal volunteers were treated in a randomized, crossover design with triazolam or placebo and underwent positron emission tomography at night. During wakefulness and stage 2 and slow wave (stages 3 and 4) sleep, we measured mean arterial blood pressure (MAP), Paco2, and absolute CBF. With triazolam compared to placebo, MAP reduced gradually. During stage 2 sleep, Paco2 increased and whole-brain mean CBF decreased. With triazolam, relative rCBF of the left orbital basal forebrain decreased more during stage 2 than slow wave sleep, whereas absolute CBF of the occipital cortex and cerebral white matter remained constant. During triazolam-induced stage 2 sleep, absolute CBF of the cerebral white matter correlated more strongly to both MAP and Paco2 than during placebo sleep and also correlated more strongly to both MAP and Paco2 than absolute CBF of the occipital cortex. In the frontal white matter, during triazolam-induced stage 2 sleep compared to wakefulness, absolute CBF was significantly better correlated to MAP, but not to Paco2. During triazolam-induced stage 2, the cerebral white matter may receive a modulated CBF regulation having the strengthened relationship of Paco2 to CBF and, more locally, the frontal white matter may depend precariously on CBF regulation.
Hiroki
Masahiko
M
Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan. CYI01752@nifty.com
Kajimura
Naofumi
N
Uema
Takeshi
T
Ogawa
Kenichi
K
Nishikawa
Masami
M
Kato
Masaaki
M
Watanabe
Tsuyoshi
T
Nakajima
Toru
T
Takano
Harumasa
H
Imabayashi
Etsuko
E
Ohnishi
Takashi
T
Takayama
Yutaka
Y
Matsuda
Hiroshi
H
Uchiyama
Makoto
M
Okawa
Masako
M
Takahashi
Kiyohisa
K
Fukuyama
Hidenao
H
D000328:Adult; D001785:Blood Gas Monitoring, Transcutaneous; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D001921:Brain / Q000000981:diagnostic imaging; D002245:Carbon Dioxide / Q000097:blood*; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D018592:Cross-Over Studies; D005133:Eye Movements / Q000502:physiology; D005625:Frontal Lobe / Q000098:blood supply; D006801:Humans; D006993:Hypnotics and Sedatives / Q000494:pharmacology*; D008297:Male; D009778:Occipital Lobe / Q000098:blood supply; D010313:Partial Pressure; D049268:Positron-Emission Tomography; D012039:Regional Blood Flow / Q000187:drug effects; D012890:Sleep / Q000187:drug effects / Q000502:physiology*; D012894:Sleep Stages / Q000187:drug effects / Q000502:physiology; D014229:Triazolam / Q000494:pharmacology*
D006993:Hypnotics and Sedatives; D002245:Carbon Dioxide; D014229:Triazolam