PT  - JOURNAL ARTICLE
AU  - J. F. MORAN
AU  - M. MAY
AU  - H. KIMELBERG
AU  - D. J. TRIGGLE
TI  - Studies on the Noradrenaline α-Receptor
DP  - 1967 Jan 01
TA  - Molecular Pharmacology
PG  - 15--27
VI  - 3
IP  - 1
4099  - http://molpharm.aspetjournals.org/content/3/1/15.short
4100  - http://molpharm.aspetjournals.org/content/3/1/15.full
SO  - Mol Pharmacol1967 Jan 01; 3
AB  - Studies have been made of the potential usefulness of adrenergic blocking 2-halogenoethylamines for labeling time α-receptor. The uptake of 3H-labeled N-(2-bromoethyl)-N-ethyl-N-1-naphthylmethylamine (3H-SY.28) by rabbit vas deferens was shown to be nonspecific and the 2-halogenoethylamine apparently showed little specificity for the α-receptor. In an attempt to obtain greater specificity, rabbit aorta and vas deferens were pretreated with N,N-dimethyl-2-bromo-2-phenylethylamine, a short-lasting irreversible α-receptor antagonist, prior to treatment with 3H-SY.28. Tissues pretreated with the short-lasting antagonist should take up less 3H-SY.28 and the difference between this uptake and that of controls should reflect the concentration of α-receptor material. However, this treatment did not afford any significant protection against the uptake of 3H-SY.28. The possible protective effects of various amines against labeling by 3H-SY.28 were also investigated: no correlation could be found between the protective ability of these amines and their "direct" or "indirect" sympathomimetic activities. An investigation was also made of the finding that trypsin can reverse the blockade of 3H-SY.28. It was concluded that the recovery of response following trypsin is probably unrelated to α-receptor regeneration. The distribution of 3H-SY.28 and its corresponding alcohol was studied in rats. Our results suggest that the prolonged tissue retention of radioactivity following 3H-SY.28 is probably due to the high binding capacities of tissues for 3H-SY.28 alcohol rather than to the presence of high concentrations of covalently bound 3H-SY.28. ACKNOWLEDGMENTS The authors wish to thank Miss Marlene Calderone for her technical assistance. This work was supported by Grant GM 11603 from the United States Public Health Service.