Skip to main content
Fig. 2 | The Journal of Physiological Sciences

Fig. 2

From: Effects and biological limitations of +Gz acceleration on the autonomic functions-related circulation in rats

Fig. 2

The mean responses of renal sympathetic nerve activity (rSNA) and arterial pressure at the level of the brain (brain AP) to +3.0 Gz acceleration in nine rats without anti-G equipment. rSNA was recorded from the postganglionic renal nerve using stainless-steel electrodes (AS633, Cooner Wire, Chatsworth, CA, USA) fixed by silicone gel (SIL604S-A and -B, Kagawa-Kikai, Japan) in rats anesthetized with urethane as described in Fig. 1. The background noise was determined by enough hypertension to suppress RSNA with phenylephrine. Nerve activity was expressed in %, calculated as [RSNA activity × 100/resting RSNA level observed in the control period]. Refer details on nerve recordings in [22, 35, 36]. The loaded Gz is expressed as a logarithmic scale. Acceleration of +3.0 Gz without anti-G equipment decreased brain AP from 90 ± 3 to 23 ± 11 mmHg, and increased rSNA from 100 to 142 ± 31 %. The peak time of increase in rSNA was somewhat earlier than that of deepest decline in brain AP, indicating that rSNA was beginning to decrease, but did not reach to a zero level, which indicates not a ‘Resignation Response’ phenomenon (see in text) [17, 22, 25, 30]

Back to article page