Right atrial pressure and ANP release during prolonged exercise in a hot environment

Abstract

To investigate the relationship between right atrial pressure (RAP) and atrial natriuretic peptide (ANP) release during prolonged exercise in a hot environment (30 degrees C, 20% relative humidity), we studied with a Swan-Ganz catheter five male volunteers exercising on a cycle ergometer at 60% of peak aerobic power for 50 min. The ANP level increased from 14 +/- 3 (SE) to 69 +/- 10 pg/ml (P < 0.001) during the first 10 min of exercise as RAP rose from 4.3 +/- 0.8 to 6.9 +/- 1.1 mmHg (P < 0.001). The 10-min ANP level was significantly correlated with RAP (r = 0.88, P < 0.05) but not with heart rate, pulmonary arterial blood temperature, plasma norepinephrine, or plasma epinephrine. The 10-min RAP value was inversely correlated with blood volume (r = -0.98, P < 0.01) and also with stroke volume (r = -0.96, P < 0.01). In the next 20 min of exercise, ANP continued to increase to 101 +/- 12 pg/ml (P < 0.02 vs. 10 min) and remained at this level until 50 min of exercise, whereas RAP decreased and reached a level not significantly different from baseline at 50 min (5.7 +/- 1.0 mmHg; P < 0.01 vs. 10 min). This dissociation of ANP and RAP may have been related to the significant increases from the 10-min values of heart rate, blood temperature, norepinephrine (all P < 0.01), and epinephrine (P < 0.02) during the same period. These results suggest that ANP release is primarily controlled by atrial distension at the onset of exercise but that other stimulators may be involved thereafter.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial plasma ANP and NH2‐terminal proANP during right atrial pressure increase in humans

“…In man, head-out immersion (Ogihara et al 1986, Epstein et al 1987, Leung et al 1987, Warner et al 1991, Nakamitsu et al 1994, or headdown tilt (Allen et al 1989, Arjamaa et al 1992 are among the factors that elevate plasma ANP. Nose et al (1994), measuring the right atrial pressure with an intraluminal catheter, showed a correlation between plasma ANP and right atrial pressure during prolonged exercise in man.…”

Intradermal Administration of Atrial Natriuretic Peptide Attenuates Cutaneous Vasodilation but Not Sweating in Young Men during Exercise in the Heat

“…Atrial natriuretic peptide (ANP) is an important volume-regulating hormone that is released by cardiac muscle cells in response to elevations in right atrial pressure [1][2][3][4]. Under conditions of volume expansion, circulating ANP reduces the central blood volume through its natriuretic and diuretic actions [5].…”

“…Under conditions of volume expansion, circulating ANP reduces the central blood volume through its natriuretic and diuretic actions [5]. Prolonged exercise in the heat also stimulates plasma ANP release, initially via atrial distension and then by progressive increases in heart rate associated with rising body temperatures and plasma catecholamine levels [2,6]. Under these conditions, higher circulating ANP concentrations are associated with larger blood volume reductions caused by sweat-induced dehydration [2].…”

“…Prolonged exercise in the heat also stimulates plasma ANP release, initially via atrial distension and then by progressive increases in heart rate associated with rising body temperatures and plasma catecholamine levels [2,6]. Under these conditions, higher circulating ANP concentrations are associated with larger blood volume reductions caused by sweat-induced dehydration [2]. Combined, these findings indicate that ANP may compromise central blood volume and cardiac filling during prolonged exercise in the heat, especially when fluid volume is not adequately restored [6].…”

Atrial natriuretic peptide and aldosterone synthase gene in essential hypertension: A case–control study

“…ANP is released by distension, primarily from atrial tissue in healthy subjects (Nose et al, 1994). It has been proved that plasma ANP levels acted as a regulatory factor in the development of hypertension (Levin et al, 1998).…”