Central Actions of Opiates and Opioid Peptides

摘要: The in vivo study of opiates and opioid peptides is complicated by the multiple receptor affinities drugs presently available (Wood et al., 1981b; Wood, 1982a; 1983a). This property majority compounds for demands that both extensive dose—response studies naloxone reversibility be performed. If possible, stereospecificity agonist actions reversal an antagonist should examined 1984b). A further complication also evident; namely, species differences appear to dependent upon proportion mu, delta, kappa receptors a brain area (Gillan Kosterlitz, 1982; 1983a,b; Frischknecht 1983) pre-synaptic postsynaptic on given neuronal population Richard, 1982). Multiple types same neuron may complication; however, problems dualism via separate populations have been clearly demonstrated In this example, Ag/Ant butorphanol, which possesses bell-shaped curve with regard increases striatal dopamine metabolites, has initial action directly neurons subsequently antagonized another at caudal substantia nigra