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Effects of pentobarbital, chloralose and urethane on renal sympathetic nerve activity in awake cats
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Effects of pentobarbital, chloralose and urethane on renal sympathetic nerve activity in awake cats Kanji M a t s u k a w a and Ishio N i n o m i y a
Department of Cardiac Pl~ysiology, National Cardiovascular Center. Research Institute. Suita. Japan
Renal sympathetic nerve activity, arterial blood pressure and heart rate were simultaneously measured before and after induction of anaesthesia with pentobarbital, chloralose or urethane. We examined the time course and the magnitude of the changes in the three parameters over a period of 5 h under anaesthesia, with either spontaneous or artificial ventilation. In both respiratory conditions sympathetic nerve activity, blood pressure and heart rate decreased and then increased under pentobarbital; chloralose induced a sustained increase in sympathetic nerve activity, but left blood pressure and heart rate unchanged. Urethane produced a transient increase in nerve activity but left, under artificial ventilation, blood pressure and heart rate unchanged. To examine the baroreflex response of renal sympathetic nerves, arterial pressure was raised to 150 m m Hg with norepinephrine and lowered to 65 m m Hg with nitroprusside. Renal sympathetic nerve activity changed in inverse relation to the changes in arterial pressure in both the awake and the anaesthetized state. Under pentobarbital anaesthesia, by comparison with the conscious state, this inverse relationship curve was initially shifted downward and subsequently upward, and the slope of the curve was initially decreased. In contrast, under chloralose anaesthesia the blood pressure-nerve activity curve was shifted only upward and its slope increased. In conclusion the three anaesthetic drugs affected differently and with a different timing the tonic and reflex activity of renal sympathetic nerves of the cat.
(The Autonomic Nervous System, 26: 19-24, 1989)
Cerebral blood flow in orthostatic dysregulation Michiko Miyakawa
Department of Pediatrics. Nihon University School of Medicine, Tokyo. Japan
We studied the changes in cerebral blood flow induced by posture in children with and without orthostatic dysregulation. The cerebral blood flow was measured by transcranial doppler flowmeter and the pulsatility index was calculated. We examined 22 children with orthostatic dysregulation (10 males, 12 females), age range 10-15, and 17 controls, age range 7-15. In the standing position, the pulsatility index in the control group decreased continuously for 30 s, whereas in the orthostatic dysregulation patients it increased for 15 s and decreased thereafter. We concluded that children with orthostatic dysregulation have a decreased cerebral blood flow on assuming an upright position when compared to control subjects.
(The Autonomic Nervous System, 26: 25-30, 1989)
Effects of pentobarbital, chloralose and urethane on renal sympathetic nerve activity in awake cats Kanji M a t s u k a w a and Ishio N i n o m i y a
Department of Cardiac Pl~ysiology, National Cardiovascular Center. Research Institute. Suita. Japan
Renal sympathetic nerve activity, arterial blood pressure and heart rate were simultaneously measured before and after induction of anaesthesia with pentobarbital, chloralose or urethane. We examined the time course and the magnitude of the changes in the three parameters over a period of 5 h under anaesthesia, with either spontaneous or artificial ventilation. In both respiratory conditions sympathetic nerve activity, blood pressure and heart rate decreased and then increased under pentobarbital; chloralose induced a sustained increase in sympathetic nerve activity, but left blood pressure and heart rate unchanged. Urethane produced a transient increase in nerve activity but left, under artificial ventilation, blood pressure and heart rate unchanged. To examine the baroreflex response of renal sympathetic nerves, arterial pressure was raised to 150 m m Hg with norepinephrine and lowered to 65 m m Hg with nitroprusside. Renal sympathetic nerve activity changed in inverse relation to the changes in arterial pressure in both the awake and the anaesthetized state. Under pentobarbital anaesthesia, by comparison with the conscious state, this inverse relationship curve was initially shifted downward and subsequently upward, and the slope of the curve was initially decreased. In contrast, under chloralose anaesthesia the blood pressure-nerve activity curve was shifted only upward and its slope increased. In conclusion the three anaesthetic drugs affected differently and with a different timing the tonic and reflex activity of renal sympathetic nerves of the cat.
(The Autonomic Nervous System, 26: 19-24, 1989)
Cerebral blood flow in orthostatic dysregulation Michiko Miyakawa
Department of Pediatrics. Nihon University School of Medicine, Tokyo. Japan
We studied the changes in cerebral blood flow induced by posture in children with and without orthostatic dysregulation. The cerebral blood flow was measured by transcranial doppler flowmeter and the pulsatility index was calculated. We examined 22 children with orthostatic dysregulation (10 males, 12 females), age range 10-15, and 17 controls, age range 7-15. In the standing position, the pulsatility index in the control group decreased continuously for 30 s, whereas in the orthostatic dysregulation patients it increased for 15 s and decreased thereafter. We concluded that children with orthostatic dysregulation have a decreased cerebral blood flow on assuming an upright position when compared to control subjects.
(The Autonomic Nervous System, 26: 25-30, 1989)