Activity of neurons of the cerebral A5 zone of rat induced by adequate stimulation of muscle afferents: On the control of arterial pressure and respiration during muscle activity

Abstract

In experiments on 24 anesthetized rats with preserved spontaneous respiration, we first recorded the volley impulse activity of neurons (n = 30) in the brainstem А5 zone, which was induced by periodical stretchings of the forelimb flexors and hindlimb extensors. The frequency of action potentials in such volleys was, on average, 99.7 ± 19.6 sec -1 . In the course of this kinesthetic stimulation, along with the activation of "proprioceptive" neurons of the А5 zone, we observed transitory drops in the arterial pressure and increases in the frequency and intensity of multineuronal discharges in the phrenic nerve. In these experiments, we first recorded the activity of baroceptive neurons in subpial parts of the А5 zone (n = 4); the frequency of their background impulsation was, on average, 25.1 ± 0.8 sec -1 . This activity in all cases was transitorily suppressed both upon increases of the blood pressure caused by constriction of the carotid arteries or nociceptive tail stimulation, as well as upon stretching of skeletal muscles. Therefore, we first obtained direct proof that neuronal systems of the А5 zone are involved in integration of visceral and somatic proprioceptive afferent influences. We hypothesize that the physiological role of this mechanism of integration of somatic and visceral information at the level of the А5 zone is directed toward lowering of the arterial pressure and intensification of respiration within the period of intensified motor activity. This mechanism is based on the interaction between "proprioceptive," baroceptive, and, perhaps, multiceptive neurons within the А5 zone.

Integrative function of proprioceptive system in the acute effects of whole body vibration on the movement performance in young adults

“…The integrative properties of the proprioceptive system at the CNS segmental level are manifested by the tonic vibration reflex (16, 17) and tendon reflexes (6,18) with recruitment of the maximum number of motor units of skeletal muscles (16,19). At the stem level, proprioceptive interneurons integrate vegetative functions (blood circulation, respiration) (20)(21)(22), nociception (9) and balance (23) during WBV. The integrative properties of the proprioceptive system at the level of the hypothalamus elicits neuroendocrine responses, and at the level of sensorimotor cortical areas (M1) (15,24) participates in the control of motor activity, improves cognitive function and psychological well-being such as mood (25,26).…”

Physiological Studies on the Cardiopulmonary Index Changes in Adaptation to Progressive Physical Loads

“…Physiologists' understanding is increasingly shifting from the initial denial that the CRS exists as an independent functional unit, towards understanding an exceptional significance of its adaptive role [11][12][13][14][15]. In previous articles [16][17], we have described a number of distinctions and disadvantages in studying this problem at the current stage.…”