Stimulation of splenic and lymphocytic acetylcholinesterase and adenosine deaminase activities in Rhamdia quelen experimentally infected with Pseudomonas aeruginosa: Impairment of immune system

Appropriate control of immune responses is a critical determinant of fish health. The cholinergic and adenosinergic systems have important roles in the immune response, since acetylcholine (ACh) and adenosine (Ado) possess important anti-inflammatory properties and modulate the immune response during infectious diseases. Thus, the aim of this study was to evaluate whether splenic and lymphocytic adenosinergic and cholinergic systems are able to modulate the immune response during Pseudomonas aeruginosa infection. Acetylcholinesterase (AChE) and adenosine deaminase (ADA) activities in spleen tissue and splenic lymphocytes increased in infected animals compared to uninfected animals. Moreover, plasmatic and splenic metabolites of nitric oxide (NOx) increased in infected animals compared to uninfected animals. Therefore, our results support the hypothesis that the cholinergic and adenosinergic systems are not able to modulate the immune response against P. aeruginosa. In summary, increased AChE and ADA activities exert a pro-inflammatory profile, impairing the immune system and contributing to inflammatory damage.