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Further Studies on sympathetic hyperfunction in motor neuron disease
ABSTRACTS: The Autonomic Nervous System
Further Studies on Sympathetic Hyperfunction in Motor Neuron Disease Naotoshi Tamura, Kunio Shimazu, Toshimasa Yamamoto, Seietsu Watanabe, Atsuhiro Onoda, Kaori Itokawa and Katsuhiko Hamaguchi
Department of Neurology, Saitama Medical Schoo~ Saitama 350-04, Japan While it is generally accepted that there is no involvement of the autonomic nervous system in motor neuron disease, some reports have suggested the possibility of an increased sympathetic function. In this study we have therefore examined systematically the sympathetic function in 13 patients with motor neuron disease and in 10 control subjects. These were the main findings: (i) haemodynamic tests showed that the overshoot of the blood pressure in the Valsalva's maneuver was significantly greater in patients than in controls. The reflex hypertension in response to the cold pressor tests also tended to be elevated among the patients; (ii) the increase in blood pressure following an intravenous administration of noradrenaline was blunted in motor neuron disease patients; (iii) the effects of administration of isoproterenol on pulse rate and blood pressure were not different in patients and in controls; (iv) the plasma noradrenaline level was significantly higher in patients than in controls, whereas the plasma adrenaline level did not differ between the two groups; and (v) patients with motor neuron disease had an increased urinary secretion rate ofvanillylmandelie acid, methoxyhydroxy-phenylglyeol and normetanephrine, but not of homovanillie acid or metanephrine. These results dearly indicate that in patients with motor neuron disease there is an increased release of noradrenaline from sympathetic nerve fibres. (The Autonomic Nervous System, 28: 357-363, 1991)
Chemical Stimulation of the Locus Coeruleus: Inhibitory Effects on Blood Pressure, Heart Rate and Renal Sympathetic Nerve Activity Takashi Miyawaki, I-Iiroshi Kawamura and Michinobu Hatano
Second Department of Internal Medicine, Nihon University School of Medicine, Tokyo 173, Japan We studied the role of the locus coeruleus in the regulation of arterial pressure, heart rate and renal sympath-
231
etic nerve activity, by means of a microinjection technique in anesthetized rats. Unilateral mieroinjection of the excitatory amino acid L-glutamate into the locus coeruleus increased the neuronal activity of the locus coeruleus and elicited a dose-dependent decrease in blood pressure and heart rate. In response to this chemical stimulation there was also a transient but strong inhibition of the renal sympathetic nerve activity. The responses were not affected by severing the ascending projections of the locus coeruleus with a midbrain transection. In contrast, injection of the inhibitory amino acid 7-aminobutyric acid (GABA) or the a2-adrenergie agonist clonidine into the locus coeruleus decreased the neuronal activity in this nucleus, but there was no effect on arterial pressure or heart rate. We concluded that: (i) the neurons of the locus eoeruleus exert an inhibitory effect on the sympathetic nervous system, and the chemical stimulation of these neurons elicits a depressor and bradycardic response; (ii) these inhibitory responses are not mediated by the ascending projections of the locus eoeruleus, but by its descending projections; and (iii) the neurons of the locus coeruleus have no tonic effect on the cardiovascular system. o
(The Autonomic Nervous System, 28: 364-370, 1991)
Autoradiographic Studies on Binding Sites of 3HNot'adrenaline in the Gastric Fundus of Rat: Role in Secretion and Microclrculation Masahiko Nakamura*, Masaya Oda**, Jun Inoue**, Atsuko Morishita**, Takashi Ito**, Yasuo Fujishiro*** and Masaharu Tsuchiya**
*Department of Internal Medicine, ***Department of Surgery, Tokyo Demyoku Hospital, Tokyo 160, and **Department of Internal Medicine~ School of Medicine; Keio University, Tokyo 160, Japan We investigated by autoradiography the binding site for 3H-noradmnaline in freeze-dried specimens of rat stomach (autoradiography of the soluble compounds) and in routinely-fLxed specimens, with the aim of clarifying the effect ofnoradrenaline on the fundic portion of the stomach. An aqueous solution o f 3H-noradrenaline mixed with various concentrations of cold ligand were infused through an intra-aortic catheter. Immediately after the infusion, the stomach was removed and its wall cut into small blocks with a razor blade. For autoradiography of the soluble compounds, the blocks were
Further Studies on Sympathetic Hyperfunction in Motor Neuron Disease Naotoshi Tamura, Kunio Shimazu, Toshimasa Yamamoto, Seietsu Watanabe, Atsuhiro Onoda, Kaori Itokawa and Katsuhiko Hamaguchi
Department of Neurology, Saitama Medical Schoo~ Saitama 350-04, Japan While it is generally accepted that there is no involvement of the autonomic nervous system in motor neuron disease, some reports have suggested the possibility of an increased sympathetic function. In this study we have therefore examined systematically the sympathetic function in 13 patients with motor neuron disease and in 10 control subjects. These were the main findings: (i) haemodynamic tests showed that the overshoot of the blood pressure in the Valsalva's maneuver was significantly greater in patients than in controls. The reflex hypertension in response to the cold pressor tests also tended to be elevated among the patients; (ii) the increase in blood pressure following an intravenous administration of noradrenaline was blunted in motor neuron disease patients; (iii) the effects of administration of isoproterenol on pulse rate and blood pressure were not different in patients and in controls; (iv) the plasma noradrenaline level was significantly higher in patients than in controls, whereas the plasma adrenaline level did not differ between the two groups; and (v) patients with motor neuron disease had an increased urinary secretion rate ofvanillylmandelie acid, methoxyhydroxy-phenylglyeol and normetanephrine, but not of homovanillie acid or metanephrine. These results dearly indicate that in patients with motor neuron disease there is an increased release of noradrenaline from sympathetic nerve fibres. (The Autonomic Nervous System, 28: 357-363, 1991)
Chemical Stimulation of the Locus Coeruleus: Inhibitory Effects on Blood Pressure, Heart Rate and Renal Sympathetic Nerve Activity Takashi Miyawaki, I-Iiroshi Kawamura and Michinobu Hatano
Second Department of Internal Medicine, Nihon University School of Medicine, Tokyo 173, Japan We studied the role of the locus coeruleus in the regulation of arterial pressure, heart rate and renal sympath-
231
etic nerve activity, by means of a microinjection technique in anesthetized rats. Unilateral mieroinjection of the excitatory amino acid L-glutamate into the locus coeruleus increased the neuronal activity of the locus coeruleus and elicited a dose-dependent decrease in blood pressure and heart rate. In response to this chemical stimulation there was also a transient but strong inhibition of the renal sympathetic nerve activity. The responses were not affected by severing the ascending projections of the locus coeruleus with a midbrain transection. In contrast, injection of the inhibitory amino acid 7-aminobutyric acid (GABA) or the a2-adrenergie agonist clonidine into the locus coeruleus decreased the neuronal activity in this nucleus, but there was no effect on arterial pressure or heart rate. We concluded that: (i) the neurons of the locus eoeruleus exert an inhibitory effect on the sympathetic nervous system, and the chemical stimulation of these neurons elicits a depressor and bradycardic response; (ii) these inhibitory responses are not mediated by the ascending projections of the locus eoeruleus, but by its descending projections; and (iii) the neurons of the locus coeruleus have no tonic effect on the cardiovascular system. o
(The Autonomic Nervous System, 28: 364-370, 1991)
Autoradiographic Studies on Binding Sites of 3HNot'adrenaline in the Gastric Fundus of Rat: Role in Secretion and Microclrculation Masahiko Nakamura*, Masaya Oda**, Jun Inoue**, Atsuko Morishita**, Takashi Ito**, Yasuo Fujishiro*** and Masaharu Tsuchiya**
*Department of Internal Medicine, ***Department of Surgery, Tokyo Demyoku Hospital, Tokyo 160, and **Department of Internal Medicine~ School of Medicine; Keio University, Tokyo 160, Japan We investigated by autoradiography the binding site for 3H-noradmnaline in freeze-dried specimens of rat stomach (autoradiography of the soluble compounds) and in routinely-fLxed specimens, with the aim of clarifying the effect ofnoradrenaline on the fundic portion of the stomach. An aqueous solution o f 3H-noradrenaline mixed with various concentrations of cold ligand were infused through an intra-aortic catheter. Immediately after the infusion, the stomach was removed and its wall cut into small blocks with a razor blade. For autoradiography of the soluble compounds, the blocks were