Static handgrip exercise modifies arterial baroreflex control of vascular sympathetic outflow in humans

Kamiya, Atsunori; Michikami, Daisaku; Fu, Qi; Niimi, Yoshiji; Iwase, Satoshi; Mano, Tadaaki; Suzumura, Akio

doi:10.1152/ajpregu.2001.281.4.r1134

Cited by 68 publications

(104 citation statements)

References 32 publications

(57 reference statements)

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“…In this scenario, EAAs would exert a dual action on the vasomotor RVLM neurons by mediating the chemoreflex or metaboreflex-evoked sympathoexcitation and also by increasing the sympathetic baroreflex responsiveness to changes in blood pressure. The previous findings that static exercise is accompanied by a strong increase in the gain of the muscle sympathetic baroreflex while hypoxia increases the RSNA baroreflex gain are in line with such a possibility (24,28). This can be regarded as a protective mechanism that buffers an excessive sympathoexcitation evoked by these reflexes to optimize the cardiovascular homeostasis in a given physiological or pathological situation.…”

Section: Perspectivesmentioning

confidence: 55%

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: Perspectivesmentioning

confidence: 55%

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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“…It was demonstrated that change in forearm position may have an impact on sympathetic nerves in muscles of hand 35) . However, reports are concentrated on forearm raise together with handgrip exercises performed more or less intensively, which could cause the increase in sympathetic activity 35,36) . For these reasons we think that results of our experiments were not ultimately interfered by holding a telephone.…”

Section: Discussionmentioning

confidence: 99%

The Influence of the Call with a Mobile Phone on Heart Rate Variability Parameters in Healthy Volunteers

Andrzejak

Poręba

et al. 2008

Ind Health

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It is possible that electromagnetic field (EMF) generated by mobile phones (MP) may have an influence on the autonomic nervous system (ANS) and modulates the function of circulatory system. The aim of the study was to estimate the influence of the call with a mobile phone on heart rate variability (HRV) in young healthy people. The time and frequency domain HRV analyses were performed to assess the changes in sympathovagal balance in a group of 32 healthy students with normal electrocardiogram (ECG) and echocardiogram at rest. The frequency domain variables were computed: ultra low frequency (ULF) power, very low frequency ( The tone of the parasympathetic system measured indirectly by analysis of heart rate variability was increased while sympathetic tone was lowered during the call with use of a mobile phone. It was shown that the call with a mobile phone may change the autonomic balance in healthy subjects. Changes in heart rate variability during the call with a mobile phone could be affected by electromagnetic field but the influence of speaking cannot be excluded.

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“…The sensitivity of the control exerted by the arterial baroreflexes (carotid and aortic baroreflexes together) over muscle sympathetic nerve activity (MSNA) has been shown to be elevated during both static handgrip exercise and PEMI (8,9). Very recently, Ichinose et al (6) reported that the modification of the arterial baroreflex control of MSNA that is seen during PEMI could be a consequence of a muscle metaboreflex-induced alteration in the baroreflex control of both the occurrence and strength of MSNA bursts.…”

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confidence: 99%

Muscle metaboreflex modulates the arterial baroreflex dynamic effects on peripheral vascular conductance in humans

Ichinose¹,

Nishiyasu²

2005

American Journal of Physiology-Heart and Circulatory Physiology

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by the ultrasound Doppler method), leg vascular conductance (LVC), mean arterial blood pressure (MAP), and heart rate (HR)] in humans. In 12 healthy subjects (10 men and 2 women), who performed sustained 1-min handgrip exercise at 50% maximal voluntary contraction followed immediately by an imposed postexercise muscle ischemia (PEMI), 5-s periods of neck pressure (NP; 50 mmHg) or neck suction (NS; Ϫ60 mmHg) were used to evaluate carotid baroreflex function both at rest (Con) and during PEMI. First, the decreases in LVC and LBF and the augmentation of MAP elicited by NP were all greater during PEMI than in Con (⌬LVC, Ϫ1.2 Ϯ 0.2 vs. Ϫ1.9 Ϯ 0.2 ml ⅐ min Ϫ1 ⅐ mmHg Ϫ1 ; ⌬LBF, Ϫ97.3 Ϯ 11.2 vs. Ϫ177.0 Ϯ 21.8 ml/min; ⌬MAP, 6.7 Ϯ 1.2 vs. 11.5 Ϯ 1.4 mmHg, Con vs. PEMI; each P Ͻ 0.05). Second, in Con, NS significantly increased both LVC and LBF (⌬LVC, 0.9 Ϯ 0.2 ml ⅐ min Ϫ1 ⅐ mmHg Ϫ1 ; ⌬LBF, 46.6 Ϯ 9.8 ml/min; significant change from baseline: each P Ͻ 0.05), and, whereas during PEMI no significant increases in LVC and LBF occurred during NS itself (⌬LVC, 0.2 Ϯ 0.1 ml ⅐ min Ϫ1 ⅐ mmHg Ϫ1 ; ⌬LBF, 10.8 Ϯ 9.6 ml/min; each P Ͼ 0.05), a decrease was evident in each parameters at 5 s after the cessation of NS. Third, during PEMI, the decrease in MAP elicited by NS was smaller (⌬MAP, Ϫ8.4 Ϯ 1.0 vs. Ϫ5.8 Ϯ 0.4 mmHg, Con vs. PEMI; P Ͻ 0.05), and it recovered to its initial level more quickly after NS (vs. Con). Finally, however, the HR responses to NS and NP were not different between PEMI and Con. These results suggest that during muscle metaboreflex activation in humans, the arterial baroreflex dynamic effect on peripheral vascular conductance is modulated, as exemplified by 1) an augmentation of the NP-induced LVC decrease, and 2) a loss of the NS-induced LVC increase. skeletal muscle metaboreflex; carotid baroreflex; exercise DURING HEAVY EXERCISE, the arterial baroreflexes and the reflexes evoked by activation of those afferent nerve endings in the working skeletal muscles that are sensitive to metabolic changes (the so-called muscle metaboreflex) are hypothesized to be activated and, moreover, to interact in ways that lead to modulation of the primary cardiovascular reflex responses (6 -9, 15, 19, 20, 24, 25, 29, 31). Two types of interaction between these reflexes have been demonstrated to lead to such modulation. In the first type, the arterial baroreflexes act to oppose the pressor response elicited via the muscle metaboreflex (15,19,29,31). Evidence for this effect has been obtained during dynamic exercise in dogs (31) as well as during static handgrip exercise (29) and postexercise muscle ischemia (PEMI) in humans (15). The second type of interaction involves a modulation of arterial baroreflex function during muscle metaboreflex activation (6 -9, 20). However, these interactions (especially the second: viz. modulation of arterial baroreflex function by the muscle metaboreflex) and their consequences are not fully understood.Papelier et al. (20) found that during PEMI-induced muscle metaboreflex activation, the carotid sin...

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Static handgrip exercise modifies arterial baroreflex control of vascular sympathetic outflow in humans

Cited by 68 publications

References 32 publications

Glutamate receptors in RVLM modulate sympathetic baroreflex in conscious rabbits

Glutamate receptors in RVLM modulate sympathetic baroreflex in conscious rabbits

The Influence of the Call with a Mobile Phone on Heart Rate Variability Parameters in Healthy Volunteers

Muscle metaboreflex modulates the arterial baroreflex dynamic effects on peripheral vascular conductance in humans

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