In vivo binding in rat brain and radiopharmaceutical preparation of radioiodinated HEAT, an alpha-1 adrenoceptor ligand.
In vivo binding of [125I]-2-[beta-(3-iodo-4-hydroxyphenyl)ethylaminomethyl tetralone) ([125I]HEAT) to alpha-1 adrenoceptors in the rat brain was determined over 4 hr. Uptake in the thalamus and frontal cortex was approximately 0.1% injected dose per gram tissue. Thalamus/cerebellum ratios of 10:1 and frontal cortex/cerebellum ratios of 5:1 were found at 4 hr. Pretreatment with prazosin, an alpha-1 antagonist, completely inhibited the accumulation of [125I]HEAT in thalamus and frontal cortex; yet uptake of radioactivity was not significantly affected by antagonists and agonists for other receptors classes (propranolol, beta-1; apomorphine, D-1; spiperone, D-2). Binding of [125I]HEAT is saturable. At 4 hr, [125I]HEAT or [123I]HEAT was shown to be the only radioactive material in rat thalamus and frontal cortex. Iodine-123 HEAT and [125I]HEAT were synthesized as radiopharmaceuticals within 3 hr in 99% radiochemical purity.
D000317:Adrenergic alpha-Antagonists / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000378:metabolism*; D007457:Iodine Radioisotopes; D007553:Isotope Labeling / Q000379:methods; D008297:Male; D010627:Phenethylamines / Q000378:metabolism*; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D044024:Tetralones
D000317:Adrenergic alpha-Antagonists; D007457:Iodine Radioisotopes; D010627:Phenethylamines; D011942:Receptors, Adrenergic, alpha; D044024:Tetralones; C010652:BE 2254