Year-end Sale % OFF 
Abstract
Primary cultures of myocardial cells from neonatal rats were exposed for up to 5 days to the cyclic AMP derivative 8-Br-cAMP. After one day of exposure to the nucleotide, an increase in specific binding capacity of the hydrophilic beta-adrenoceptor antagonist 3H-CGP 12177 was observed in intact cells. (-)-Isoprenaline displaced the radioligand from its binding site. Neither the KD of the antagonist, nor that of the agonist were significantly affected by 8-Br-cAMP. The loss of beta-adrenoceptors during desensitization by long term treatment of the cells with isoprenaline could be partially prevented by 8-Br-cAMP. Only in desensitized, but not in normal cells was isoprenaline-induced cAMP formation significantly enhanced by 8-Br-cAMP pretreatment. This may indicate that beta-adrenoceptors which appear during 8-Br-cAMP exposure are poorly coupled to the adenylate cyclase. Alternatively, the change in receptor density may be accompanied by alterations of other components in the beta-adrenergic system, e.g. an inhibition of the adenylate cyclase. We suggest that cAMP-dependent feed-back regulation of the beta-adrenergic system may play a role during postnatal myocardial differentiation.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
