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John C. Longhurst - One of the best experts on this subject based on the ideXlab platform.

Roger A. L. Dampney - One of the best experts on this subject based on the ideXlab platform.

  • Modulation of the baroreceptor reflex by the dorsomedial hypothalamic nucleus and perifornical area
    American journal of physiology. Regulatory integrative and comparative physiology, 2005
    Co-Authors: Lachlan M. Mcdowall, Jouji Horiuchi, Suzanne Killinger, Roger A. L. Dampney
    Abstract:

    Neurons within the dorsomedial hypothalamic nucleus (DMH) and perifornical area (PeF), which lie within the classic hypothalamic defense area, subserve the Cardiovascular Response to psychological ...

  • Activation of 5-Hydroxytryptamine 1A Receptors Suppresses the Cardiovascular Response Evoked From the Dorsomedial Hypothalamic Nucleus
    Hypertension (Dallas Tex. : 1979), 2005
    Co-Authors: Jouji Horiuchi, Sonoe Wakabayashi, Roger A. L. Dampney
    Abstract:

    The dorsomedial hypothalamic nucleus is a key component of the central pathways subserving the Cardiovascular Response to psychological stress, which is believed to be an important risk factor for hypertension. Previous studies indicate that 5-hydroxytryptamine 1A receptors can modulate the Cardiovascular Responses associated with stress. In this study, we determined in anesthetized rats the effects of systemic or intracisternal administration of 8-hydroxy-2-(di-n-propylamino)tetralin, a selective agonist of 5-hydroxytryptamine 1A receptors, and then subsequent administration of the selective antagonist WAY-100635 on the Cardiovascular Response evoked by activation of the dorsomedial hypothalamic nucleus (by microinjection of bicuculline). The increase in mean arterial pressure, heart rate, and renal sympathetic nerve activity (RSNA) evoked by bicuculline injection into the dorsomedial hypothalamic nucleus was greatly reduced (by 80% to 90%) by administration of 8-hydroxy-2-(di-n-propylamino)tetralin and then completely restored by subsequent administration of WAY-100635, whether administered systemically or intracisternally. In contrast, systemic administration of 8-hydroxy-2-(di-n-propylamino)tetralin had no significant effect on the baseline level or reflex changes in RSNA evoked by chemoreceptor or baroreceptor stimulation and resulted in only a modest reduction (12 mm Hg) in baseline mean arterial pressure. The results indicate that activation of 5-hydroxytryptamine 1A receptors in the brain stem causes a potent and selective suppression of the hypertensive and sympathoexcitatory Response evoked by stimulation of the dorsomedial hypothalamic nucleus but has little effect on the tonic level or baroreceptor or chemoreceptor reflex control of RSNA.

  • Descending pathways mediating Cardiovascular Response from dorsomedial hypothalamic nucleus.
    American journal of physiology. Heart and circulatory physiology, 2001
    Co-Authors: Marco Antônio Peliky Fontes, T. Tagawa, Jaimie W. Polson, S.-j. Cavanagh, Roger A. L. Dampney
    Abstract:

    Physiological and anatomic methods were used to determine whether neurons in the rostral ventrolateral medulla (RVLM), nucleus tractus solitarius (NTS), or hypothalamic paraventricular nucleus (PVN) mediate the Cardiovascular Response evoked from the dorsomedial hypothalamic nucleus (DMH), which is believed to play a key role in mediating Responses to stress. In urethane-anesthetized rats, activation of neurons in the DMH by microinjection of bicuculline resulted in a large increase in arterial pressure, heart rate, and renal sympathetic nerve activity. The pressor and sympathoexcitatory Responses, but not the tachycardic Response, were greatly reduced after bilateral muscimol injections into the RVLM even when baseline arterial pressure was maintained at a constant level. These Responses were not reduced by muscimol injections into the PVN or NTS. Retrograde tracing experiments identified many neurons in the DMH that projected directly to the RVLM. The results indicate that the vasomotor and cardiac components of the Response evoked from the DMH are mediated by pathways that are dependent and independent, respectively, of neurons in the RVLM.

Tatiana Kuznetsova - One of the best experts on this subject based on the ideXlab platform.

  • impact of age sex and heart rate variability on the acute Cardiovascular Response to isometric handgrip exercise
    Journal of Human Hypertension, 2021
    Co-Authors: Nicholas Cauwenberghs, Veronique Cornelissen, Jeffrey W Christle, Kristofer Hedman, Jonathan Myers, Francois Haddad, Tatiana Kuznetsova
    Abstract:

    Isometric handgrip exercise (IHG) triggers acute increases in cardiac output to meet the metabolic demands of the active skeletal muscle. An abnormal Cardiovascular Response to IHG might reflect early stages of Cardiovascular disease. In a large community-based cohort, we comprehensively assessed the clinical correlates of acute Cardiovascular changes during IHG. In total, 333 randomly recruited subjects (mean age, 53 ± 13 years, 45% women) underwent simultaneous echocardiography and finger applanation tonometry at rest and during 3 min of IHG at 40% maximal handgrip force. We calculated time-domain measures of short-term heart rate variability (HRV) from finger pulse intervals. We assessed the adjusted associations of changes in blood pressure (BP) and echocardiographic indexes with clinical characteristics and HRV measures. During IHG, men presented a stronger absolute increase in heart rate, diastolic BP, left ventricular (LV) volumes and cardiac output than women, even after adjustment for covariables. In adjusted continuous and categorical analyses, age correlated positively with the increase in systolic BP and pulse pressure, but negatively with the increase in LV stroke volume and cardiac output during exercise. After full adjustment, a greater increase in systolic and diastolic BP during exercise was associated with lower absolute real variability (P ≤ 0.026) and root mean square of successive differences (P ≤ 0.032) in pulse intervals at rest. In a general population sample, women presented a weaker Cardiovascular Response to IHG than men. Older age was associated with greater rise in BP pulsatility and diminished cardiac reserve. Low HRV at rest predicted a higher BP increase during isometric exercise.

Jonathan Myers - One of the best experts on this subject based on the ideXlab platform.

  • impact of age sex and heart rate variability on the acute Cardiovascular Response to isometric handgrip exercise
    Journal of Human Hypertension, 2021
    Co-Authors: Nicholas Cauwenberghs, Veronique Cornelissen, Jeffrey W Christle, Kristofer Hedman, Jonathan Myers, Francois Haddad, Tatiana Kuznetsova
    Abstract:

    Isometric handgrip exercise (IHG) triggers acute increases in cardiac output to meet the metabolic demands of the active skeletal muscle. An abnormal Cardiovascular Response to IHG might reflect early stages of Cardiovascular disease. In a large community-based cohort, we comprehensively assessed the clinical correlates of acute Cardiovascular changes during IHG. In total, 333 randomly recruited subjects (mean age, 53 ± 13 years, 45% women) underwent simultaneous echocardiography and finger applanation tonometry at rest and during 3 min of IHG at 40% maximal handgrip force. We calculated time-domain measures of short-term heart rate variability (HRV) from finger pulse intervals. We assessed the adjusted associations of changes in blood pressure (BP) and echocardiographic indexes with clinical characteristics and HRV measures. During IHG, men presented a stronger absolute increase in heart rate, diastolic BP, left ventricular (LV) volumes and cardiac output than women, even after adjustment for covariables. In adjusted continuous and categorical analyses, age correlated positively with the increase in systolic BP and pulse pressure, but negatively with the increase in LV stroke volume and cardiac output during exercise. After full adjustment, a greater increase in systolic and diastolic BP during exercise was associated with lower absolute real variability (P ≤ 0.026) and root mean square of successive differences (P ≤ 0.032) in pulse intervals at rest. In a general population sample, women presented a weaker Cardiovascular Response to IHG than men. Older age was associated with greater rise in BP pulsatility and diminished cardiac reserve. Low HRV at rest predicted a higher BP increase during isometric exercise.

Mathias Baumert - One of the best experts on this subject based on the ideXlab platform.