Effects of anesthesia on cardiac and renal sympathetic nerve activities and plasma catecholamines

Matsukawa, Kanji; Ninomiya, Ishio; Nishiura, Naoki

doi:10.1152/ajpregu.1993.265.4.r792

Cited by 58 publications

(48 citation statements)

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“…The lack of the effect of kynurenate appeared to be due to the pentobarbital sodium anesthesia severely compromising the baroreflex gain, which is likely to limit the ability of the premotor neurons to be further inhibited. The strong inhibiting action of barbiturate anesthesia on the baroreflex gain has also been reported previously (18,31). Although other commonly used anesthetics, such as urethane and chloralose, generally inhibit baroreflexes to a lesser extent (19,37), chloralose-urethane still reduces the RSNA baroreflex gain to ϳ60% of the value in conscious rabbits (10,11).…”

Section: Discussionsupporting

confidence: 66%

Glutamate receptors in RVLM modulate sympathetic baroreflex in conscious rabbits

Mayorov

Head

2003

American Journal of Physiology-Regulatory, Integrative and Comp

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In this study, we examined the effect of excitatory amino acid (EAA) receptor blockade in the rostral ventrolateral medulla (RVLM) on the renal sympathetic baroreflex in conscious rabbits. Rabbits were implanted with guide cannulas for bilateral microinjections into the RVLM (ϩ2 to ϩ3 mm from the obex, n ϭ 8) or into the intermediate ventrolateral medulla (IVLM; 0 to ϩ1 mm from the obex, n ϭ 5) and with an electrode for measuring renal sympathetic nerve activity (RSNA). After 7 days of recovery, microinjection of the EAA receptor antagonist kynurenate (10 nmol) into the RVLM did not affect resting RSNA or arterial pressure. Kynurenate decreased the gain of the RSNA baroreflex by 53% but did not change the reflex range. By contrast, injection of kynurenate into the IVLM increased resting arterial pressure and RSNA by 27 mmHg and 88%, respectively, but did not alter the RSNA baroreflex gain or range. Pentobarbital sodium anesthesia attenuated the gain and range of the RSNA baroreflex by 78 and 40%, respectively. Under these conditions, microinjection of kynurenate into the RVLM did not cause any further change in the gain of this reflex. These results suggest that endogenous EAA neurotransmitters in the RVLM are important in modulating the sympathetic baroreflex in conscious rabbits. Anesthesia can mask the functional significance of EAAs in the RVLM in modulating the baroreflexes, which may explain why previous studies in anesthetized animals found no effect of blocking EAA receptors in the RVLM on sympathetic baroreflexes. excitatory amino acids; kynurenate; arterial pressure; anesthesia; heart rate THE PRESSOR REGION of the rostral ventrolateral medulla (RVLM) is critical in the generation and maintenance of sympathetic activity and is also an essential part of the central baroreflex pathways (8,9,15). The GABAergic synapse is believed to be a principal relay in the RVLM in transmission of baroreceptor information, because blockade of GABA receptors in this area abolished the vasomotor component of the reflex (8,15). By contrast, the excitatory amino acids (EAAs) in the RVLM are thought to play a little role in mediating cardiovascular responses to baroreceptor stimulation. This assumption is supported by numerous findings that the blockade of ionotropic EAA receptors in the region with local administration of kynurenate did not affect sympathetic baroreflexes in rats (27, 40), rabbits (41), or cats (12). This contrasts with the essential role of EAAs in the RVLM in mediating many other cardiovascular reflexes. In particular, administration of kynurenate into the RVLM has been shown to attenuate the pressor and sympathoexcitatory reflex responses to hypothalamic stimulation (40), muscular contraction (4), noxious stimulation (34), and renal and vagal afferent stimulation (6, 41) in anesthetized animals. Furthermore, this also contrasts with the ability of glutamate, given into the RVLM, to enhance the sympathetic baroreflex, indicating that local glutamate-sensitive inputs may also play a role in modulating bar...

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Section: Discussionsupporting

confidence: 66%

Glutamate receptors in RVLM modulate sympathetic baroreflex in conscious rabbits

Mayorov

Head

2003

American Journal of Physiology-Regulatory, Integrative and Comp

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“…The nerve discharges recorded from the feline inferior cardiac nerve, therefore, are considered to originate from sympathetic postganglionic efferent fibers. We found that the cardiac sympathetic nerve is tonically active in the conscious state, but it is very susceptible to anesthesia (17); its firing rate in mass discharge is relatively high (54 Ϯ 12 impulses/s). Obviously this result indicates an existence of basal cardiac sympathetic outflow in the resting condition of conscious cats.…”

Section: Discussionmentioning

confidence: 87%

“…From our previous studies (17,22), the arterial baroreflex sensitivity of CSNA is 1.4-2.3%/ mmHg during resting in conscious cats. It has been considered that the sensitivity of the arterial barore-…”

Section: Discussionmentioning

confidence: 89%

“…The amplified output was fed into a bandpass filter between 150 and 3,000 Hz. Sympathetic discharges were converted into standard pulse trains using a digital technique that detected the peaks of the original neural spikes (17,23). The pulse trains were integrated continuously with a resistance-capacitance integrator having a time constant of 20 ms.…”

Section: Methodsmentioning

confidence: 99%

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Direct measurement of cardiac sympathetic efferent nerve activity during dynamic exercise

Tsuchimochi

Matsukawa

Komine

et al. 2002

American Journal of Physiology-Heart and Circulatory Physiology

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The assumption that tachycardia during light to moderate exercise was predominantly controlled by withdrawal of cardiac parasympathetic nerve activity but not by augmentation of cardiac sympathetic nerve activity (CSNA) was challenged by measuring CSNA during treadmill exercise (speed, 10–60 m/min) for 1 min in five conscious cats. As soon as exercise started, CSNA and heart rate (HR) increased and mean arterial pressure (MAP) decreased; their time courses at the initial 12-s period of exercise were irrespective of the running speed. CSNA increased 168–297% at 7.1 ± 0.4 s from the exercise onset, and MAP decreased 8–13 mmHg at 6.0 ± 0.3 s, preceding the increase of 40–53 beats/min in HR at 10.5 ± 0.4 s. CSNA remained elevated during the later period of exercise, whereas HR and MAP gradually increased until the end of exercise. After the cessation of exercise, CSNA returned quickly to the control, whereas HR was slowly restored. In conclusion, cardiac sympathetic outflow augments at the onset of and during dynamic exercise even though the exercise intensity is low to moderate, which may contribute to acceleration of cardiac pacemaker rhythm.

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“…injected. After catecholamines were purified from plasma, a catecholamine assay was performed by reversed-phase high-pressure liquid chromatography with electrochemical detection according to our previous studies [7][8][9].…”

Section: Methodsmentioning

confidence: 99%

Reflex Responses in Plasma Catecholamines Caused by Static Contraction of Skeletal Muscle.

Matsukawa

Sadamoto²,

Tsuchimochi³

et al. 2001

JJP

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Muscle contraction activates small muscular afferents (myelinated group III and unmyelinated group IV fibers), which is believed to initiate autonomic reflex adjustment of the cardiovascular system. It was demonstrated that sympathetic outflows to the heart and the kidneys increase during static muscle contraction induced by electrical stimulation of the ventral roots in anesthetized cats [1][2][3][4]. The increase in cardiac sympathetic nerve activity correlates with an increase in heart rate [3], and the increase in renal sympathetic nerve activity correlates with reduced renal blood flow [2], suggesting that the reflex changes in postganglionic sympathetic nerve activities caused by skeletal muscle contraction contribute to cardiovascular adjustments, such as increases in cardiac output and arterial blood pressure and a redistribution of car-591Japanese Journal of Physiology, 51, 591-597, 2001 Key words: norepinephrine, epinephrine, adrenal medulla, adrenal sympathetic nerve activity, mechanical stretch of muscle. Abstract:To examine a hypothesis of whether static muscle contraction produces a release of catecholamines from the adrenal medulla via reflex stimulation of preganglionic adrenal sympathetic nerve activity induced by receptors in the contracting muscle, we compared the reflex responses in a concentration of epinephrine (Ep) and norepinephrine (NEp) in arterial plasma during static contraction and during a mechanical stretch of the hindlimb triceps surae muscle in anesthetized cats. Static contraction was evoked by electrically stimulating the peripheral ends of the cut L 7 and S 1 ventral roots at 20 or 40 Hz. Mean arterial pressure (MAP) and heart rate (HR) increased 23Ϯ3.1 mmHg and 19Ϯ4.3 beats/min during static contraction. Ep in arterial plasma increased 0.18Ϯ0.072 ng/ml over the control of 0.14Ϯ0.051 ng/ml within 1 min from the onset of static contraction, and NEp increased 0.47Ϯ0.087 ng/ml over the control of 0.71Ϯ 0.108 ng/ml. Following a neuromuscular blockade, although the same ventral root stimulation failed to produce the cardiovascular and plasma catecholamine responses, the mechanical stretch of the muscle increased MAP, HR, and plasma Ep, but not plasma NEp. With bilateral adrenalectomy, the baseline Ep became negligible (0.012Ϯ0.001 ng/ml) and the baseline NEp was lowered to 0.52Ϯ0.109 ng/ml. Neither static contraction nor mechanical stretch produced significant responses in plasma Ep and NEp following the adrenalectomy. These results suggest that static muscle contraction augments preganglionic adrenal sympathetic nerve activity, which in turn secretes epinephrine from the adrenal medulla into plasma. A muscle mechanoreflex from the contracting muscle may play a role in stimulation of the adrenal sympathetic nerve activity.

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Effects of anesthesia on cardiac and renal sympathetic nerve activities and plasma catecholamines

Cited by 58 publications

References 0 publications

Glutamate receptors in RVLM modulate sympathetic baroreflex in conscious rabbits

Glutamate receptors in RVLM modulate sympathetic baroreflex in conscious rabbits

Direct measurement of cardiac sympathetic efferent nerve activity during dynamic exercise

Reflex Responses in Plasma Catecholamines Caused by Static Contraction of Skeletal Muscle.

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