caa a22 4500 465738753 CHVBK 20180323111802.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF02245785 doi (NATIONALLICENCE)springer-10.1007/BF02245785 Naloxone-induced analgesia and morphine supersensitivity effects are contingent upon prior exposure to analgesic testing [Elektronische Daten] [Constantine Poulos, Della Knoke, A. Le, Howard Cappell] Repeated administration of naloxone have been found to result in the development of analgesia. Pretreatment with naloxone can also produce supersensitivity to morphine. This study examined whether the development of these phenomena is affected by exposure to pain (hotplate testing) during opiate blockade. During acquisition, two experimental groups of rats received identical treatment with respect to repeated naloxone injections (5 mg/kg) and the environment in which the injections were administered. A "contingent” group (NAL-C) received hot-plate testing under the influence of naloxone, while a "noncontingent” group (NAL-NC) experienced hot-plate testing and naloxone separated by an interval of 24 h. At test, NAL-C rats manifested naloxone-induced analgesia (NIA) whereas the NAL-NC animals did not. The NAL-C rats also showed supersensitivity to the analgesic effects of morphine (3 mg/kg) and to the cataleptic effects of morphine (17.5 mg/kg) while the NAL-NC rats did not differ from saline controls. Thus, both NIA and morphine supersensitivity were completely dependent on testing in the drug state during acquisition; mere exposure to an identical regime of naloxone injections was insufficient to produce these phenomena. Springer-Verlag, 1990 Analgesia nationallicence Catalepsy nationallicence Contingency nationallicence Morphine nationallicence Naloxone nationallicence Naloxone-induced analgesia nationallicence Poulos Constantine Addiction Research Foundation, 33 Russell Street, M5S 2S1, Toronto, Ontario, Canada aut Knoke Della Addiction Research Foundation, 33 Russell Street, M5S 2S1, Toronto, Ontario, Canada aut Le A. Addiction Research Foundation, 33 Russell Street, M5S 2S1, Toronto, Ontario, Canada aut Cappell Howard Addiction Research Foundation, 33 Russell Street, M5S 2S1, Toronto, Ontario, Canada aut Psychopharmacology Springer-Verlag 100/1(1990-03-01), 31-35 0033-3158 100:1<31 1990 100 213 https://doi.org/10.1007/BF02245785 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02245785 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Poulos Constantine Addiction Research Foundation, 33 Russell Street, M5S 2S1, Toronto, Ontario, Canada aut NATIONALLICENCE 700 1- Knoke Della Addiction Research Foundation, 33 Russell Street, M5S 2S1, Toronto, Ontario, Canada aut NATIONALLICENCE 700 1- Le A. Addiction Research Foundation, 33 Russell Street, M5S 2S1, Toronto, Ontario, Canada aut NATIONALLICENCE 700 1- Cappell Howard Addiction Research Foundation, 33 Russell Street, M5S 2S1, Toronto, Ontario, Canada aut NATIONALLICENCE 773 0- Psychopharmacology Springer-Verlag 100/1(1990-03-01), 31-35 0033-3158 100:1<31 1990 100 213 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer