Solubilized dopamine/neuroleptic receptors (D2-type)

Abstract

• 1.

  1. Dopamine (D₂-type) receptors were solubilized from striatum of three species (human, canine, calf) using digitonin.

• 2.

  2. The receptors were labeled with ³H-spiperone and assayed by Sephadex G-50 columns or polyethylene glycol precipitation.

• 3.

  3. The soluble receptors from canine and human tissue had similar K_d's and rank order of drug affinities to the membrane-bound sites.

• 4.

  4. Soluble calf receptors showed reduced affinity for spiperone and chlorpromazine (12-fold). Non-specific binding also increased.

• 5.

  5. Solubilized canine binding was insensitive to ascorbate, Mn⁺⁺, and ethylenediamine tetracetic acid (EDTA) in contrast to the membrane binding sites.

• 6.

  6. Solubilized canine striatum serves as an excellent source of D₂ receptors because these receptors are stable in solution and are a prototype of human D₂ receptors.