[Catecholamine levels in plasma and beta2-adrenoreceptor-dependent synthesis of cAMP in lymphocytes of patients with primary pulmonary hypertension].

AIM: To evaluate norepinephrine (NE) and epinephrine (E) plasma concentration and lymphocyte beta-2-adrenoceptor dependent cAMP synthesis in primary pulmonary hypertension (PPH) patients in comparison with healthy controls.

MATERIAL AND

METHODS

Seven volunteers and fifteen patients with PPH were included in the study. NE and E plasma levels were measured by high performance liquid chromatography. Basal and stimulated (isoproterenol and forskolin) adenylyl cyclase activity in lymphocytes was measured by cAMP production using an enzyme immunoassay (Biotrak, Amersham UK).

RESULTS

There was a 110% (p = 0.001) NE level increase in PPH patients. In systolic pulmonary artery pressure (SPAP) > 95 mm Hg lymphocyte cAMP production associated with adenylyl cyclase catalytic subunit was decreased by 170% and 70% vs PPH patients with SPAP < 95 mm Hg and healthy controls, respectively (p < 0.05). A significant negative correlation between forskolin cAMP production by lymphocytes and SPAP level was observed in PPH patients (k = -0.810, p = 0.011 by Kendell; k = -0.893, p = 0.007 by Spirman). Heart failure progressing from I-II to III NYHA functional classes was accompanied by plasma NE enhance and lymphocyte beta-2-adrenoreceptor-activated cAMP production decrease.

CONCLUSION

The data demonstrate sympathoadrenal system activation and lymphocyte beta-2-adrenoceptor desensitization in PPH patients.