title: Beta 2-adrenoceptor density of human lymphocytes after nitroprusside-induced hypotension.
abstract: The present study was undertaken to assess the influence of nitroprusside-induced hypotension on beta 2-adrenoceptor density. Twenty-four patients undergoing nose-septum corrections under general anesthesia were allocated randomly to a nitroprusside or control group. beta 2-Receptor density on lymphocytes was measured by binding studies using (-)125-iodocyanopindolol. Lymphocyte subpopulations B, T, Thelper, Tsuppressor, and natural killer cells were determined simultaneously by flow cytometry. Five of 12 nitroprusside-treated patients developed significant intraoperative increases of epinephrine levels (+69% versus preoperatively) which were not seen in the remaining seven patients. In these five patients, beta 2-receptor density of unfractionated lymphocytes was 26% lower (P < 0.05) on the first day after surgery compared with preoperative values. Since no changes in proportions of lymphocyte subpopulations were observed, these results are not caused by redistribution phenomena inducing a decrease of subsets with a high number of beta receptors. These findings suggest that beta 2-adrenergic responsiveness might be diminished after nitroprusside treatment in some patients.
mesh_terms: D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001402:B-Lymphocytes / Q000187:drug effects / Q000473:pathology; D004837:Epinephrine / Q000097:blood; D005434:Flow Cytometry; D006801:Humans; D007023:Hypotension, Controlled; D007457:Iodine Radioisotopes; D020120:Iodocyanopindolol; D007694:Killer Cells, Natural / Q000187:drug effects / Q000473:pathology; D018655:Lymphocyte Count / Q000187:drug effects; D008214:Lymphocytes / Q000737:chemistry / Q000187:drug effects*; D009300:Nasal Septum / Q000601:surgery; D009599:Nitroprusside / Q000494:pharmacology*; D009638:Norepinephrine / Q000097:blood; D010869:Pindolol / Q000031:analogs & derivatives; D018343:Receptors, Adrenergic, beta-2 / Q000032:analysis / Q000187:drug effects*; D013601:T-Lymphocytes / Q000187:drug effects / Q000473:pathology; D006377:T-Lymphocytes, Helper-Inducer / Q000187:drug effects / Q000473:pathology; D050378:T-Lymphocytes, Regulatory / Q000187:drug effects / Q000473:pathology
chemical_list: D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D007457:Iodine Radioisotopes; D018343:Receptors, Adrenergic, beta-2; D009599:Nitroprusside; D020120:Iodocyanopindolol; D010869:Pindolol; D009638:Norepinephrine; D004837:Epinephrine