title: [Effect of the endogenous catecholamines synthesized by lymphocytes on T cell proliferation].
abstract: OBJECTIVE
  To provide further evidence for the synthesis of catecholamines (CAs) in lymphocytes and to investigate the effect of the endogenous CAs synthesized by lymphocytes on function of the lymphocytes themselves and the receptor mechanisms involved in the effect.
  
  
  METHODS
  RT-PCR was performed to detect the expression of TH mRNA in the lymphocytes from the mesenteric lymph nodes of rats. Different concentrations of pargyline, an inhibitor of monoamine oxydase, and antagonists of alpha1-, alpha2-, beta1-, and beta2-adrenergic receptor (AR) were added to the lymphocyte cultures, and then proliferative response of the lymphocytes to mitogen concanavalin A (Con A) were measured via methyl-thiazole-tetrazolium (MTT) assay.
  
  
  RESULTS
  The lymphocytes could express TH mRNA, and the expression of TH mRNA was significantly higher in the Con A-activated lymphocytes than in the resting ones. The treatment of pargyline of 10(-6) and 10(-5) mol/L (not 10(-7) mol/L) notably attenuated Con A-induced lymphocyte proliferation. Beta2-AR antagonist ICI118551 (10(-7) and 10(-6) mol/L) completely blocked, but alpha1-AR antagonist corynanthine and alpha2-AR antagonist yohimbine (10(-7) and 10(-6) mol/L) partly blocked the suppressive effect of pargyline on the Con A-induced lymphocyte proliferation. Nevertheless, atenolol, an antagonist of beta1-AR, had no blocking effect on pargyline inhibition of lymphocyte proliferation.
  
  
  CONCLUSIONS
  Lymphocytes have the ability to synthesize CAs and the ability is enhanced in the activated lymphocytes. The endogenous CAs synthesized by lymphocytes can inhibit T cell proliferation and the inhibition of T cells by the CAs is mediated predominantly by beta2-AR on the lymphocytes.
authors.affiliation: Department of Physiology, School of Medicine, Nantong University, Nantong 226001 China.
authors.forename: Jian-Lan
authors.initials: JL
authors.lastname: Jiang
authors.forename: Yu-Ping
authors.initials: YP
authors.lastname: Peng
authors.forename: Yi-Hua
authors.initials: YH
authors.lastname: Qiu
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000818:Animals; D002395:Catecholamines / Q000096:biosynthesis / Q000502:physiology*; D049109:Cell Proliferation / Q000187:drug effects*; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000378:metabolism*; D008297:Male; D015213:Neuroimmunomodulation / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000502:physiology; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism
chemical_list: D002395:Catecholamines; D012333:RNA, Messenger; D011943:Receptors, Adrenergic, beta; D003208:Concanavalin A; D014446:Tyrosine 3-Monooxygenase