Catecholamine content and in vitro catecholamine synthesis in peripheral human lymphocytes

Abstract

We studied the catecholamine (CA) content in peripheral human lymphocytes and the ability of these cells to synthesize CA in vitro. CA were separated by high performance liquid chromatography (HPLC) and determined in the supernatant by electrochemical detection as well as being determined after ultrasonic cell disruption in mononuclear leukocytes, adherent cells (monocytes/macrophages), total lymphocytes, and B- and T-cell enriched fractions. T lymphocytes contained L-Dopa and norepinephrine (NE), whereas B lymphocytes contained only L-Dopa. Lymphocytes seem to be able to synthesize NE from both L-tyrosine and L-Dopa added to the incubation medium in concentrations similar to the peripheral venous plasma (i.e. 5 x 10(-5) m and 10(-8) m, respectively). The addition of D-Dopa did not increase intracellular NE. alpha-methyl-p-L-tyrosine, benserazide, disulfiram, and fusaric acid (which are inhibitors of the enzymatic pathway) all decreased the synthesis of NE. After the addition of [3H]-L-Dopa (10(-8) m and 10(-7) m) to the incubation medium, [3H]-NE and [3H]-dopamine appeared. By increasing the concentration of L-Dopa in the medium (< 10(-6) m), CA were detected in the supernatant as well. These data show that peripheral human T lymphocytes contain and are able to synthesize CA from normal precursors in physiologic concentrations, i.e. a CA synthetic pathway is shown in nonneural cells. These data seem to support the hypothesis of autocrine and paracrine loops in the regulation of lymphocyte activity in lymphocytes taken from human cerebrospinal fluid (as suggested by other authors).

Non-traditional cytokines: How catecholamines and adipokines influence macrophages in immunity, metabolism and the central nervous system

“…In addition to their hormonal and neurotransmitter roles, catecholamines also influence immune responses, and the importance of this neural-immune cross-talk via neurotransmitters and cytokines has been increasingly recognized [2]. For instance, stimulation of the vagus nerve can regulate inflammatory cytokine production, and conversely, macrophages and lymphocytes are able to synthesize catecholamines that influence the central nervous system (CNS) [3–5]. Additionally, immune cells express adrenergic receptors and are therefore responsive to catecholamines [6].…”

Lymphocyte-Derived Catecholamines Induce a Shift of Th1/Th2 Balance toward Th2 Polarization

“…The catecholamines (CAs), including dopamine (DA), epinephrine (E) and norepinephrine (NE), were considered mainly as conventional neurotransmitters and neuroendocrine mediators; however, there is now robust evidence that they are also produced by cells of the immune system [1,2,3,4,5,6,7,8]. Our previous studies also indicate that lymphocytes express tyrosine hydroxylase (TH), a rate-limiting enzyme of CA synthesis, and the three kinds of CAs exist in lymphocytes and inhibit concanavalin A (Con A)-induced lymphocyte proliferation and interleukin (IL)-2 production through autocrine/paracrine pathways [9,10].…”

The Dopaminergic System in Peripheral Blood Lymphocytes: From Physiology to Pharmacology and Potential Applications to Neuropsychiatric Disorders

“…Four years later [38], the same research group confirmed the presence of DA, L-DOPA, and norepinephrine in PBL by electrospray ionization mass spectroscopy. In 1996, Musso et al [39] studied catecholamine content in human PBL and the ability of these cells to synthesize catecholamines in vitro . Catecholamines were separated by high performance liquid chromatography (HPLC) and electrochemical detection.…”