Receptor specific agents

Receptor Specific Agents-technetium Tagged Radiopharmaceuticals... 

The aim of the medicinal chemist is to pursue receptor specific agents. In order to minimize physiological side effects the specificity must be high and interactions with other receptors as small as possible. Many natural products have performed satisfactorily under this set of conditions. Accordingly, after some years with predominantly synthetic product research, major ventures are now again initiated to identify new drug candidates from secondary products. 

Brain imaging is stiU an active field of research in radiopharmaceutical chemistry. The compounds for brain imaging can be divided into two classes, one of which is discussed in this section. For the evaluation of the brain, one can apply either regional blood flow agents or receptor specific agents. Currently, the only Food and Drug Administration (FDA)-approved Tc radiopharmaceuticals are from the first class, so-called perfusion agents, but substantial efforts for the introduction of radiopharmaceuticals of the second class are currendy... 

Bicuculline is an isoquinoline alkaloid elaborated from members of the family Fumariaceae (Papaverales), especially in Corydalis, Dicentra, and Fumaria species. Bicuculline, like picrotoxin, is a specific GABA receptor-blocking agent that impedes the... 

The synthesis and characterization of a somatostatin receptor-specific peptide H2N-(DPhe)-cyclo[Cys-Phe-(D-Trp)-Lys-Thr-Cys]-Thr-OH, labeled with an indo-dicarbo- and an indotricarbocyanine dye at the V-terminal amino group were described in [34], The ability of these fluorescent contrast agents to target the somatostatin receptor was demonstrated by flow cytometry in vitro, wherein the indotricarbocyanine conjugate led to elevated cell-associated fluorescence on somatostatin receptor-expressing tumor cells. The intracellular localization was visualized using NIR fluorescence microscopy. 

Dopamine receptor blocking agents. Many of the neuroleptics used in the treatment of schizophrenia frequently produce parkinsonian symptoms as unwanted effects. Neuroleptics block dopamine receptors and their therapeutic effect seems to be related to this action. Although these drugs act on DA systems without distinction, some are more selective. Thioridazine, clozapine and molindone, for example, have electrophysiological effects in the limbic region of the brain but little action in the nigro-striatal area. This selectivity may be related to receptor subtype specificity (see Chs 12 and 54). 

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