著者

余 錦 佐藤 純 舟久保 恵美 小畑 光央 水村 和枝

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2004, pp.S245, 2004

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To examine the effects of change in meteorological factors on autonomic parameters in conscious animals, male Sprague-Dawley rats (n = 11) were exposed to lowering barometric pressure (LP) in a climate-controlled room. Systemic blood pressure (BP) was telemetrically recorded using a radio-transmitter equipped with a BP transducer. Heart rate (HR) was calculated from BP data and pulse interval variability was analyzed by power spectrograms obtained by the fast-Fourier transform algorithm. The low-frequency (LF: 0.02-0.6 Hz) power, high-frequency (HF: 0.8-3.0 Hz) power and LF/HF ratio, an index of relative sympathetic activity, were calculated. The rats were exposed to LP by decreasing the barometric pressure of the room by 27 hPa lower than the atmospheric pressure. This was done over 8 min. The pressure was maintained at this level for 29 min, and then returned to the baseline pressure over 8 min. The BP markedly increased after reaching the pre-set low pressure and reached the peak value at the middle of LP-exposure period. The HR and LF/HF ratio clearly rose in the early part of the LP-exposure period and then gradually decreased to the level before exposure. The LF/HF ratio also transiently increased at the recompression period. These results show that lowering barometric pressure within the range of natural environmental fluctuation induces autonomic responses in conscious rats. The increase in the LF/HF ratio during LP exposure indicates that low pressure environment induces sympathetic > parasympathetic activation. <b>[Jpn J Physiol 54 Suppl:S245 (2004)]</b>