Aporphine alkaloids receptors

The presence of the A-ring of aporphines, and the addition of substituents to it can extend explorations of the dimensions and other characteristics of the dopamine receptor. Accordin y the synthesis of a series of (—)2,10,11-trihydroxyaporphines was undertaken and their in vivo (Neumeyer et al. 1981b) and in vitro characteristics were evaluated. The enantiomers (6aR and 6aS) of 2,10,11-trihydroxyaporphine (16a, THA) were synthesized from thebaine and bulbocapnine and evaluated pharmacologically (Neumeyer et al. 1982). The (—) 1,2,11-trihydroxyaporphine (17) was prepared from the naturally occurring aporphine alkaloid (R)-pukateine (15) using boron tribromide (Ram and Neumeyer 1984). 

Most information regarding the action of alkaloids relates to the alpha 2 receptor, where the indole alkaloids yohimbine and its isomer, rauwolscine, bind with high affinity and block the receptor [187, 191]. Dihydrocorynantheine, an indole alkaloid of similar structure preferentially binds to the alpha 1 receptor, as do some aporphines [192,... 

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