Dual mode of catecholamine action on splenic macrophage phagocytosis in wall lizard, Hemidactylus flaviviridis

Norepinephrine suppresses wound macrophage phagocytic efficiency through alpha- and beta-adrenoreceptor dependent pathways

“…Norepinephrine, the primary neurotransmitter of the peripheral sympathetic nervous system, is released in large quantities from peripheral nerves into the circulation following injury and has previously been shown to be involved in wound healing (26)(27)(28)(29). While a number of studies report catecholamine-mediated alterations in the phenotype of splenic and peritoneal macrophages (20,21,30), the present study is the first to delineate a role for norepinephrine in modulation of wound macrophage phagocytic function.…”

“…(D) To determine if norepinephrine-mediated changes in phagocytosis involve the protein kinase A (PKA) signaling pathway, cells were incubated with H-89 (10 −5 M, Sigma), a specific inhibitor of PKA, for two hours prior to norepinephrine treatment as above. The dosages and treatment durations employed were chosen to allow ease of comparison with previous studies (20,21,23). …”

“…While a clear role for norepinephrine in modulation of cytokine production by macrophages exists (15)(16)(17)(18), there has been comparatively little investigation of catecholamine-mediated alterations in phagocytosis, a critical step in the wound healing process (19)(20)(21). The present study examines the role of norepinephrine in modulation of wound macrophage phagocytic function using E.coli bacteria, a biologically relevant target.…”

Dynorphin regulates the phagocytic activity of splenic phagocytes in wall lizards: involvement of a κ-opioid receptor-coupled adenylate-cyclase–cAMP–PKA pathway

“…This suggests the coupling of an opioid receptor with a stimulatory alpha subunit ( s ) of the G-protein. In our earlier in vitro study in the wall lizard, dibutyryl cAMP was shown to inhibit the percentage phagocytosis and phagocytic index at higher concentrations (Roy and Rai, 2004). Also, an increased intracellular cAMP level in cortisoltreated (Roy and Rai, 2009) and melatonin-treated (Roy et al, 2008) splenic phagocytes is reported to be directly correlated with inhibition of phagocytosis in the freshwater fish Channa punctatus.…”

Diurnal variation in phagocytic activity of splenic phagocytes in freshwater teleost Channa punctatus: melatonin and its signaling mechanism

“…Also, a decrease in intracellular cAMP is shown to enhance phagocytosis in murine peritoneal macrophages (Lima et al 1974). An inverse relationship between cAMP and phagocytic activity of splenic macrophages has been demonstrated also in wall lizards (Roy & Rai 2004). In the case of chicks, intriguingly, opposite effects of melatonin are observed on cAMP and IP3 production in the same cell depending on the activation state of cells and the involvement of specific subtypes of melatonin receptors.…”