Abstract
Para-amino-clonidine (PAC) is an α-adrenergic agonist with extraordinarily high potency in some peripheral tissues. We have demonstrated the labeling of α-adrenergic binding sites in central and peripheral tissues with [3H]PAC and compared properties of this binding to those of [3H]clonidine. [3H]PAC binds saturably with a dissociation constant (KD) of about 0.9 nM to rat cerebral cortex membranes. It has about 2-3 times the affinity of [3H]clonidine for α-receptor binding sites. The greater affinity is attributable mainly to a slower dissociation of [3H]PAC than [3H]clonidine from binding sites. The relative and absolute potencies of various adrenergic agonists and antagonists in competing for [3H]PAC and [3H]clonidine binding are essentially the same. [3H]PAC can also be utilized to label α-adrenergic binding sites in the kidney and spleen where the relative potencies of PAC and clonidine are the same as in the brain.
Original language | English (US) |
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Pages (from-to) | 769-774 |
Number of pages | 6 |
Journal | Life Sciences |
Volume | 25 |
Issue number | 9 |
DOIs | |
State | Published - Aug 27 1979 |
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)