Autonomic neuroscience : basic & clinical
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Pupillary unrest is a chaotic fluctuation in pupil size that is observed in darkness with the onset of drowsiness, and in ambient light. The mechanism of pupillary unrest in darkness as well as in ambient light is unknown but studies suggest that it is caused by fluctuating activity in the Edinger-Westphal (E. W.) nucleus. ⋯ Recovery from the drug effect was observed. Based upon the data from this study we propose that pupillary unrest in light originates within oscillating inhibitory neurons that intermittently depress the E. W. nucleus.
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We speculated that stroke volume would be higher and heart rate would be lower when the head and upper trunk were mainly upright in the Fowler's position. We therefore analyzed the effects of three trunk postures in Fowler's position on heart rate, blood pressure and circulatory volume. Heart rate (HR), blood pressure (BP), stroke volume (SV), cardiac output (Q), systemic vascular resistance (SVR), ejection time (ET) and pre-ejection period (PEP) were measured in 10 healthy male volunteers (mean age ± SEM, 20.7 ± 0.5 y; range, 19-23 y) while in three trunk postures in Fowler's position. ⋯ None of Q, SVR and BP significantly differed among the three conditions (p > 0.05). These findings suggested that SV and preload are higher when the upper trunk is upright (UT60°) than when the entire trunk is upright (WT60°) while in Fowler's position. In addition, Q might be maintained without increasing HR through vagal withdrawal when only the upper trunk is upright in healthy young males in Fowler's position.