ABSTRACT
Neuropeptides generally fulfill a dual function of neurotransmitter and of hormone in the brain and the periphery. The peptide-receptor interaction triggers changes of membrane ionic conductance and/or variations of intracellular enzymatic activity. These transduction mechanisms often involve guanyl nucleotide binding proteins as intermediates. This chapter describes the various approaches and methodologies that have been used to purify neuropeptide receptors from brain with the purpose being to underline and discusses the peculiar advantages and drawbacks of each method. A common characteristic of gels that have been used successfully in ligand affinity chromatography of neuropeptide receptors is the very high concentration of ligand bound to the gel as compared to the affinity of the free ligand for the receptor. Neuropeptide receptors purified in the free form bind to their specific radiolabeled ligands in a reversible and satuable manner and with high affinity.
