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Effects of adenosine on cAMP production during early development in the optic tectum of chicks
Author(s) -
Tasca C.I.,
Vendite D.,
Garcia K.L.,
Souza D.O.
Publication year - 1995
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/0736-5748(95)00047-k
Subject(s) - adenylate kinase , adenosine , medicine , cyclase , endocrinology , phosphodiesterase , stimulation , basal (medicine) , cyclic adenosine monophosphate , chemistry , biology , enzyme , biochemistry , receptor , insulin
Accumulation of cyclic adenosine monophosphate (cAMP) elicited by adenosine was studied in slices and membrane preparations of optic tectum from chicks aged 1–13days post‐hatch. Accumulation of cAMP promoted by adenosine declined with age, chicks and the lowest in 11‐day‐old chicks. However, when the slices were incubated with adenosine and the phosphodiesterase inhibitor‐Ro 20‐1724 the differences between teh two ages were abolished, suggesting a higher phosphodiesterase activity in 11‐day‐old chicks. In membrane preparations, although basal adenylate cyclase activity was lower in three‐day‐old chicks, the guanylyl‐imidodiphosphate (Gpp(NH)p) concentration curves for stimulation of adenylate cyclase activity indicated a higher sensitivity of G protein to Gpp(NH)p at this age. This hypothesis was reinforced by the observation that the binding of [ 3 H]Gpp(NH)p to the membrane preparation was greater in three‐day‐old animals. In spite of these differences, the percentage of adenylate cyclase activity stimulation by 2‐chloroadenosine (2CADO) + Gpp(NH)p was the same at both ages. These findings suggest that the decreased response evoked by adenosine during development is probably due to increased phosphodiesterase activity and a lower sensitivity of adenylate cyclase activity to Gpp(NH)p.