Regulation of Adenosine 3′:5′-Cyclic Monophosphate Concentration in Cultured Human Astrocytoma Cells by Catecholamines and Histamine

Abstract

Norepinephrine, epinephrine, and histamine cause a rapid increase in the concentration of adenosine 3':5'-cyclic monophosphate (cAMP) in a tumor astrocyte cell line derived from a primary culture of a human glioblastoma multiforme. The catecholamine-induced increase in cAMP is dependent on the cell density, being far greater in cells in the log phase of growth than in cells near terminal density. The response to norepinephrine is inhibited 50% by 0.01 pM propranolol, a blocking agent of #-adrenergic receptors. In contrast, the effect of histamine on cAMP concentration varies only slightly from log-phase growth to terminal density, and is not inhibited by 10 All of the known components of the cAMP regulatory system, adenylate cyclase (1), a cAMP-dependent protein kinase (2), and a cAMP-specific phosphodiesterase (3), are demonstrable in brain. Furthermore, the adenylate cyclase of brain generates cAMP in response to various effectors: e.g., putative neurotransmitters such as norepinephrine, histamine, and serotonin (4), depolarizing agents such as K + and veratridine (5), and the nucleoside, adenosine (6). However, elucidation of the exact role of cAMP has been hampered because of the anatomic and cellular complexity of brain. For example, there is great variation in the response of the adenylate cyclase system to these effectors within different brain regions (7), within the same region in different species (5), and at different stages of brain development (8). Further, since brain is composed of a number of cell types, primarily neurons and glia, measurements of enzyme activities in homogenates or of cAMP concentrations in slices will include contributions from both of these cell populations. To our knowledge, no report has appeared describing attempts to differentiate the response of the adenylate cyclase system in the two major cell types. Since neurons and glia probably have distinctly different functional capacities, an increase in the intracellular concentration of cAMP would presumably be mediated by cell-specific stimuli. In view of these considerations, studies with homogeneous cell populations of either neurons or glia should reveal whether one cell type or both are responsive to the various effectors, and ultimately should provide a rational approach to the determination of the role of cAMP in brain function. For this reason, we are characterizing the cAMP regulatory system of a human astrocytoma cell line, 1181N1, maintained in continuous culture. Adenylate cyclase, cAMP phosphodiesterase, and cAMP-dependent protein kinase are present 2757 (9), and the growth pattern and morphology of the cells is altered by N6, 02 '-dibutyryl cAMP (10). Here, we report the effects of catecholamines and histamine on the intracellular concentrations of cAMP. A preliminary report of some of the results of this investigation has appeared (11). MATERIALS AND METHODSThe cloned tumor astrocyte line, 1181N1, was originally derived from a human cerebral glioblastoma multiforme (12). The cells are grown in Eagle's mi...

Effect of adenosine deaminase inhibition upon human lymphocyte blastogenesis.

“…It had no effect on theophylline-induced inhibition of thymidine uptake, and indeed, in neuronal cells theophylline has been reported to be an inhibitor of adenosine-mediated elevations of cyclic AMP concentrations (11,23). Taken alone, these results suggest that adenosine deaminase inhibition can augment the effects of cyclic AMP.…”

The Effects of Calcium Concentration on the Inhibition of Cholinergic Neurotransmission in the Myenteric Plexus of Guinea‐pig Ileum by Adenine Nucleotides

“…There is evidence that adenosine stimulates adenylate cyclase leading to elevated cyclic AMP levels in brain tissue slices (Sattin & RalL 1970;Schultz & Daly, 1973) and nerve cells in tissue culture (Clark et al, 1974;Blume & Foster, 1975). Since an increase in cyclic AMP is associated with acetylcholine release (Goldberg & Singer, 1969;Wilson, 1974), it seems unlikely, on circumstantial grounds, that this mechanism operates in the adenine-induced inhibition of acetylcholine release that we have documented.…”

“…These include suggestions that adenosine, adenosine 5'-pyrophosphate (ADP) and adenosine 5'-triphosphate (ATP) function as neurotransmitters released by inhibitory 'purinergic' nerve endings (Burnstock, CampbelL Satchell & Smythe, 1970;Burnstock, 1972;Satchell & Burnstock, 1975;Okwuasaba, Hamilton & Cook, 1977); that their action is mediated by alterations in intracellular levels of cyclic adenosine 3',5'-monophosphate (cyclic AMP) (Sattin & Rall, 1970;Clark, Gross, Su & Perkins, 1974); or that they affect the passage of sodium (Imai Since calcium ions are critically and ubiquitously involved in the function of excitable cells, we have studied the effects of adenosine and adenine derivatives on contractile responses of the guinea-pig ileum longitudinal muscle-myenteric plexus preparation at different calcium concentrations. Our results have shown that adenosine-containing compounds act at a presynaptic site on postganglionic cholinergic neurones in the myenteric plexus and that this action may be mediated by modulation of intra-axonal calcium concentration.…”

Purinergic signalling and cancer

“…ATP, after breakdown to adenosine, increases intracellular cAMP in human 1321NI astrocytoma cells [633,634]. However, later papers showed that high concentrations of ATP, acting via P2 receptors, stimulate proliferation of SKMG-1 and U373 human astrocytoma cells [635] or inhibition of proliferation of 132NI astrocytoma cell [636].…”