Hyperthyroidism modifies ecto-nucleotidase activities in synaptosomes from hippocampus and cerebral cortex of rats in different phases of development.
Here we investigate the possible effects of the hyperthyroidism on the hydrolysis of the ATP to adenosine in the synaptosomes of hippocampus, cerebral cortex and blood serum of rats in different developmental phases. Manifestations of hyperthyroidism include anxiety, nervousness, tachycardia, physical hyperactivity and weight loss amongst others. The thyroid hormones modulate a number of physiological functions in central nervous system, including development, function, expression of adenosine A(1) receptors and transport of neuromodulator adenosine. Thus, hyperthyroidism was induced in male Wistar rats (5-, 60-, 150- and 330-day old) by daily injections of L-thyroxine (T4) for 14 days. Nucleotide hydrolysis was decreased by about 14-52% in both hippocampus and cerebral cortex in 5 to 60-day-old rats. These changes were also observed in rat blood serum. In addition, in 11-month-old rats, inhibition of ADP and AMP hydrolysis persisted in the hippocampus, whereas, in cerebral cortex, an increase in AMP hydrolysis was detected. Thus, hyperthyroidism affects the extracellular nucleotides balance and adenosine production, interfering in neurotransmitter release, development and others physiological processes in different systems.
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Avenida Ramiro Barcellos 2600-ANEXO, 90035-003, Porto Alegre, RS, Brazil.
Alessandra Nejar
AN
Bruno
Rosane Souza
RS
Da Silva
Carla Denise
CD
Bonan
Ana Maria Oliveira
AM
Battastini
Maria Luiza M
ML
Barreto-chaves
João José Freitas
JJ
Sarkis
D000227:Adenine Nucleotides / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000375:Aging; D000818:Animals; D002540:Cerebral Cortex / Q000201:enzymology* / Q000503:physiopathology; D006624:Hippocampus / Q000201:enzymology* / Q000503:physiopathology; D006868:Hydrolysis; D006980:Hyperthyroidism / Q000097:blood / Q000139:chemically induced / Q000201:enzymology* / Q000503:physiopathology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D013574:Synaptosomes / Q000201:enzymology*; D013974:Thyroxine
D000227:Adenine Nucleotides; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; C027201:ectoATPase; D013974:Thyroxine