The pedunculopontine nucleus (PPN) has previously been implicated in central command regulation of the cardiorespiratory adjustments that accompany exercise. The current study was executed to begin ...to address the potential role of the PPN in the regulation of cardiorespiratory adjustments evoked by muscle contraction. Extracellular single-unit recording was employed to document the responses of PPN neurons during static muscle contraction. Sixty-four percent (20/31) of neurons sampled from the PPN responded to static muscle contraction with increases in firing rate. Furthermore, muscle contraction-responsive neurons in the PPN were unresponsive to brief periods of hypotension but were markedly activated during chemical disinhibition of the caudal hypothalamus. A separate sample of PPN neurons was found to be moderately activated during systemic hypoxia. Chemical disinhibition of the PPN was found to markedly increase respiratory drive. These findings suggest that the PPN may be involved in modulating respiratory adjustments that accompany muscle contraction and that PPN neurons may have the capacity to synthesize muscle reflex and central command influences.
Exercise And Hypertension: A Model For Central Neural Plasiticty Kramer, Jeffery M; Beatty, Joseph A; Plowey, Edward D ...
Clinical and Experimental Pharmacology and Physiology,
January/February 2002, Letnik:
29, Številka:
1-2
Conference Proceeding, Journal Article
Recenzirano
SUMMARY
1. Physical movement is accompanied by coordinated changes in respiratory and cardiovascular activity proportional to the metabolic demands of the locomotor task. Cardiorespiratory changes ...include increases in ventilation, blood pressure and heart rate, as well as altered regional sympathetic nerve activity and blood flow.
2. The posterior hypothalamic area, a periventricular region in the caudal‐most diencephalon, has been shown to play a role in mediating the coupling of locomotion and cardiorespiratory activity. Stimulation of this brain region produces locomotor behaviour and simultaneous increases in cardiorespiratory activity that are independent of peripheral feedback from contracting muscles. Posterior hypothalamic neurons are also activated by exercise and exercise‐related stimuli, such as muscle contraction.
3. In spontaneously hypertensive rats (SHR), a deficiency in the inhibitory GABA neurotransmitter system within the posterior hypothalamic area contributes to tonically elevated levels of arterial blood pressure. We previously identified a reduction in the GABA synthesizing enzyme glutamic acid decarboxylase (GAD) within the posterior hypothalamus of SHR.
4. We have recently demonstrated that exercise can upregulate GABA‐mediated caudal hypothalamic control of cardiovascular function in SHR. Similarly, exercise increases GAD gene transcript levels in the posterior hypothalamus. Thus, we have identified a model to study exercise‐related central neural plasticity in GABAergic neurotransmitter function. Moreover, we suggest that exercise may increase cardiovascular health through changing central neural regulation of blood pressure.
1. Physical movement is accompanied by coordinated changes in respiratory and cardiovascular activity proportional to the metabolic demands of the locomotor task. Cardiorespiratory changes include ...increases in ventilation, blood pressure and heart rate, as well as altered regional sympathetic nerve activity and blood flow. 2. The posterior hypothalamic area, a periventricular region in the caudal-most diencephalon, has been shown to play a role in mediating the coupling of locomotion and cardiorespiratory activity. Stimulation of this brain region produces locomotor behaviour and simultaneous increases in cardiorespiratory activity that are independent of peripheral feedback from contracting muscles. Posterior hypothalamic neurons are also activated by exercise and exercise-related stimuli, such as muscle contraction. 3. In spontaneously hypertensive rats (SHR), a deficiency in the inhibitory GABA neurotransmitter system within the posterior hypothalamic area contributes to tonically elevated levels of arterial blood pressure. We previously identified a reduction in the GABA synthesizing enzyme glutamic acid decarboxylase (GAD) within the posterior hypothalamus of SHR. 4. We have recently demonstrated that exercise can upregulate GABA-mediated caudal hypothalamic control of cardiovascular function in SHR. Similarly, exercise increases GAD gene transcript levels in the posterior hypothalamus. Thus, we have identified a model to study exercise-related central neural plasticity in GABAergic neurotransmitter function. Moreover, we suggest that exercise may increase cardiovascular health through changing central neural regulation of blood pressure.
Hypothalamus, hypertension, and exercise KRAMER, Jeffery M; PLOWEY, Edward D; BEATTY, Joseph A ...
Brain research bulletin,
2000, Letnik:
53, Številka:
1
Journal Article
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