[Effect of apomorphine on rat brain opiate receptors].
Stereospecific binding of apomorphine to rat brain opiate receptors was shown by assaying the competition of 7,8(n)--3H--naloxone and D-ala2-tyrosyl-3,5-3H--enkephalin (5-D-leucine) for opiate receptor binding. EC-NaCl50, the concentration of apomorphine which inhibited 50% binding of the radioactive naloxone and D-ala2, D-leu5-enkephalin in the absence of NaCl were 20 and 42 microM, respectively. EC+NaCl 50, the concentration of apomorphine which inhibited 50% binding of the radioactive naloxone in the presence of 100 mM NaCl was 17 microM. From the ratio of EC+NaCl 50 to EC-NaCl the value of "sodium shift" of effective concentration can be calculated as 0.85. From the data obtained it is concluded that apomorphine, like naloxone, is a "pure" antagonist but it has much less affinity for enkephalin and opiate binding sites. The probable mechanisms of the pharmacological action of apomorphine are discussed.
D000818:Animals; D001058:Apomorphine / Q000378:metabolism* / Q000494:pharmacology; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D004745:Enkephalins / Q000378:metabolism; D008297:Male; D009270:Naloxone / Q000378:metabolism; D051381:Rats; D011957:Receptors, Opioid / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology
D004745:Enkephalins; D011957:Receptors, Opioid; D009270:Naloxone; D012965:Sodium Chloride; D001058:Apomorphine
Vliianie apomorfina na opiatnye retseptory golovnogo mozga krys.