Premium
Use of a newly developed technique to isolate rat pinealoeytes and study the effects of adenosine agonists on melatonin production
Author(s) -
Nicholls Julia,
Skene Debra J.,
Hourani Susanna M.O.
Publication year - 1997
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1997.tb00350.x
Subject(s) - pinealocyte , melatonin , adenosine , medicine , endocrinology , isoprenaline , agonist , adenosine receptor , biology , pineal gland , receptor , chemistry , stimulation
Nicholls J, Skene DJ, Hourani SMO. Use of a newly developed technique to isolate rat pinealoeytes and study the effects of adenosine agonists on melatonin production. J. Pineal Res. 1997; 23:164–168. © Munksgaard, Copenhagen Abstract Recent studies have suggested a role for adenosine in the regulation of rat pineal melatonin synthesis. The data, however, are conflicting and therefore the aim of this study was to characterize adenosine receptors more fully in vitro by using a range of selective adenosine agonists and the adenosine antagonist 8‐sulphophenyltheophylline (8‐SPT). A simple method for the mechanical separation of rat pinealoeytes was developed. Pinealoeytes were briefly (15 min) incubated with drugs followed by a 4 hr drug‐free incubation period after which melatonin concentrations in the incubation medium were measured by radioimmunoassay. The β‐adrenoceptor agonist isoprenaline gave a dose‐related increase in melatonin production, demonstrating that this pinealocyte preparation technique is suitable to evaluate the effect of drugs on pineal melatonin synthesis. Our results show that adenosine, N 6 ‐(phenylisopropyl)adenosine (R‐PIA) and 2‐p‐(2‐carboxethyl) phenethylamino‐5 '‐N‐ethylcarboxamidoadenosine (CGS21680) did not affect melatonin synthesis alone or in combination with isoprenaline. However 5'‐N‐ethylcarboxamidoadenosine (NEC A) (100 uM) potentiated the stimulatory effect of isoprenaline (3 μM) on pineal melatonin production and this effect appeared to be antagonized by 8‐SPT (50 uM). These results are consistent with activation by NECA of an A 2b adenosine receptor.