• Journal of Korean Academy of Nursing
• /
• v.41 no.2
• /
• pp.191-196
• /
• 2011

Purpose: We investigated the effects of group III mechanoreceptors to cardiovascular responses in both pre-menopausal woman and post-menopausal woman during passive ankle dorsiflexion (PAD). Methods: Twenty healthy volunteers (10 post-menopausal women and 10 pre-menopausal women) were recruited for this study. Stroke volume (SV), heart rate (HR), cardiac output (CO), and total vascular conductances (TVC) were measured continuously throughout the experiment. To stimulate the group III mechanoreceptors, PAD was performed for one minute. Results: The results showed that mean arterial pressure (MAP) mediated by the mechanoreflex activation was significantly increased in both groups. However, this pressor response was significantly higher in post-menopausal women. This reflex significantly increased both SV and CO in pre-menopausal women, while there were no differences in post-menopausal women. There was no difference in HR in either group. The mechanoreflex significantly decreased TVC in post-menopausal woman, while there was no difference in pre-menopausal woman. Conclusion: The results indicate that the excessive pressor response mediated by the mechanoreflex occurs due to overactivity of group III mechanorecptors and the mechanism is produced mainly via peripheral vasoconstriction in post-menopausal women.

• Journal of Life Science
• /
• v.19 no.11
• /
• pp.1568-1574
• /
• 2009

The purpose of this study was to investigate whether group III muscle afferents play an important role eliciting abnormal blood pressure response mediated during passive muscle stretch in prehypertensive individuals. Eleven middle-aged prehypertensive men (average BP 133/80 mmHg) and nine middle-aged normotensive men (average BP 119/74 mmHg) participated in this study. After 1 min rest baseline data collection, the subject's foot was flexed (dorsiflexion) by an automated cybex for one minute. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MAP), heart rate, stroke volume, cardiac output, and total peripheral resistance were continuously measured on a beat-by-beat basis from a finger via a Finapres device for 1 minute. To evaluate the role of mechanoreflex, a component of exercise pressor reflex, SBP, DBP, and MAP responses over the course of time were examined. The results showed that the pressor response mediated by the muscle mechanoreflex was faster in prehypertensive individuals compared to the normotensive individuals. The substantial pressor response was observed within mean 20 sec of the onset of passive stretch in prehypertension, while mean 45 sec in normotension (p<0.05). It is concluded that excessive pressor response produced during exercise in prehypertension may be due to the dysfunction of the mechano-receptors.