Effect of Benzodiazepine Hypnotic Triazolam on Relationship of Blood Pressure and PaCO sub(2) to Cerebral Blood Flow During Human Non-Rapid Eye Movement Sleep

• Published in: Journal of neurophysiology 2006-04, Vol.95 (4), p.2293-2303
• Main Authors: Hiroki, Masahiko, Kajimura, Naofumi, Uema, Takeshi, Ogawa, Kenichi, Nishikawa, Masami, Kato, Masaaki, Watanabe, Tsuyoshi, Nakajima, Toru, Takano, Harumasa, Imabayashi, Etsuko, Ohnishi, Takashi, Takayama, Yutaka, Matsuda, Hiroshi, Uchiyama, Makoto, Okawa, Masako, Takahashi, Kiyohisa, Fukuyama, Hidenao
• Format: Article
• Language: English
• ISSN: 0022-3077

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 (PaCO sub(2)) 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), PaCO sub(2), and absolute CBF. With triazolam compared to placebo, MAP reduced gradually. During stage 2 sleep, PaCO sub(2) 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 PaCO sub(2) than during placebo sleep and also correlated more strongly to both MAP and PaCO sub(2) 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 PaCO sub(2). During triazolam-induced stage 2, the cerebral white matter may receive a modulated CBF regulation having the strengthened relationship of PaCO sub(2) to CBF and, more locally, the frontal white matter may depend precariously on CBF regulation.