The aim of this study was to investigate adenosine receptor sites in whole brain membranes of the saltwater teleost fish, Mugil cephalus, using the Al receptor selective agonist, [H-3]- N-6-cyclohexyladenosine ([H-3]-CHA). Specific binding was saturable and reversible. A single class of high-affinity binding sites was identify, showing K-d and B-max values of 1.43 +/- 0.26 nM and 69.5 +/- 5.4 fmol/mg protein, respectively. In competition experiments, the following adenosine analogues, CHA, (2-[p-(2-carboxyethyl)-phenylethylamino]-5'-N-ethylcarboxamidoadenosine) (CGS21680), 5'-(N-cyclopropyl)carboxamidoadenosina (CPCA) and N-6-[2-(3,5-dimethoxyphenyl)-2-(2methylphenyl)-ethyl]adenosine (DPMA), displaced [H-3]-CHA specifically bound to brain membranes, revealing that the high-affinity binding sites have some pharmacological properties of mammalian Al adenosine receptors. Furthermore, our findings indicate that in captivity chemical pollution determines a decrease of the K-d value corresponding to a 5-fold increase in affinity, whereas it does not induce any variation of the receptor density. (C) 1998 Elsevier Science Ltd. All rights reserved.
Influence of chemical pollution on brain adenosine receptors of Mugil cephalus
GIANNACCINI, GINO;BETTI, LAURA;MAZZONI, MARIA ROSA;LUCACCHINI, ANTONIO
1998-01-01
Abstract
The aim of this study was to investigate adenosine receptor sites in whole brain membranes of the saltwater teleost fish, Mugil cephalus, using the Al receptor selective agonist, [H-3]- N-6-cyclohexyladenosine ([H-3]-CHA). Specific binding was saturable and reversible. A single class of high-affinity binding sites was identify, showing K-d and B-max values of 1.43 +/- 0.26 nM and 69.5 +/- 5.4 fmol/mg protein, respectively. In competition experiments, the following adenosine analogues, CHA, (2-[p-(2-carboxyethyl)-phenylethylamino]-5'-N-ethylcarboxamidoadenosine) (CGS21680), 5'-(N-cyclopropyl)carboxamidoadenosina (CPCA) and N-6-[2-(3,5-dimethoxyphenyl)-2-(2methylphenyl)-ethyl]adenosine (DPMA), displaced [H-3]-CHA specifically bound to brain membranes, revealing that the high-affinity binding sites have some pharmacological properties of mammalian Al adenosine receptors. Furthermore, our findings indicate that in captivity chemical pollution determines a decrease of the K-d value corresponding to a 5-fold increase in affinity, whereas it does not induce any variation of the receptor density. (C) 1998 Elsevier Science Ltd. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
