Related Experiment Videos
Cyclic AMP export from lymphocytes in hypertension
P J Mills1, J E Dimsdale, R A Nelesen
1Department of Psychiatry, UCSD Medical Center, University of California.
Insights
Hypertensive individuals exhibit increased cyclic AMP export from lymphocytes, independent of intracellular levels. This suggests enhanced cyclic AMP transport may play a role in hypertension.
Area of Science:
- Cardiovascular Physiology
- Cellular Biology
- Biochemistry
Background:
- Intracellular cyclic AMP (cAMP) is crucial for blood pressure regulation.
- The physiological role of cAMP exported from cells remains understudied.
Purpose of the Study:
- To investigate the relationship between blood pressure and cyclic AMP (cAMP) transport from lymphocytes.
- To determine if cAMP export differs between hypertensive and normotensive individuals.
Main Methods:
- Studied 28 hypertensive and 56 normotensive volunteers.
- Measured intracellular and extracellular cAMP concentrations in lymphocytes after isoproterenol stimulation.
- Assessed sodium excretion and beta-adrenergic receptor sensitivity.
Main Results:
- Hypertensives, especially white hypertensives, showed significantly higher levels of exported cAMP compared to normotensives.
- Intracellular cAMP levels were similar across all groups.
- Exported cAMP correlated positively with mean arterial pressure (MAP).
Conclusions:
- Active transport of cAMP from lymphocytes may be enhanced in hypertension.
- This enhanced export offers a potential explanation for elevated cAMP levels observed in hypertensive patients.
- Lymphocyte cAMP transport represents a novel pathway in blood pressure regulation.
Abstract:
While the importance of receptor-mediated intracellular cyclic AMP in blood pressure regulation is well documented, few studies have evaluated the physiologic relevance of cyclic AMP exported from cells. We report evidence of a relationship between blood pressure and the transport of intracellular cyclic AMP from lymphocytes. Twenty-eight hypertensive and 56 normotensive white and black volunteers (mean age 40 years) were studied. Both intra- and extracellular concentrations of cyclic AMP were determined in lymphocytes following incubation with 10(-5) M isoproterenol. Compared to normotensives, hypertensives (p = 0.001), particularly white hypertensives (p = 0.023) had higher levels of exported cyclic AMP. These values were independent of intracellular concentrations of cyclic AMP, which were similar across the groups. Exported cyclic AMP was independent of both sodium excretion and beta-adrenergic receptor sensitivity, the latter being lower in white hypertensives (p = 0.024). Across all subjects, exported cyclic AMP was correlated with MAP (r = .39, p < 0.001). These findings indicate that the active transport of cyclic AMP may be enhanced in hypertension and suggest a possible pathway which might explain existing data of increased cyclic AMP levels in hypertension.