{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,15]],"date-time":"2026-08-15T02:10:43Z","timestamp":1786759843561,"version":"build-2736575974"},"reference-count":0,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[1988,2,1]],"date-time":"1988-02-01T00:00:00Z","timestamp":570672000000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["The Journal of Physiology"],"published-print":{"date-parts":[[1988,2]]},"abstract":"<jats:p>1. Lactating rats were implanted with a cannula in a lateral cerebral ventricle to deliver morphine (up to 50 micrograms\/h) chronically from a subcutaneous osmotically driven mini\u2010pump. After infusion of morphine for 5 days the rats were anaesthetized with urethane and prepared with ventral surgery for recording the electrical activity of single, antidromically identified neurones in the supraoptic nucleus. 2. A single I.V. injection of naloxone (5 mg\/kg) in these rats provoked a long\u2010lasting, large increase in intramammary pressure, but in control rats had negligible effects. Concentrations in plasma of oxytocin, measured by radioimmunoassay in samples of femoral arterial blood, rose from 44.7 +\/\u2010 2.5 to 1072.1 +\/\u2010 89.5 pg\/ml (means +\/\u2010 S.E.M.) 6 min after naloxone in the morphine\u2010treated rats. In control rats, the concentration of oxytocin in plasma rose only from 42.1 +\/\u2010 2.9 to 125.1 +\/\u2010 28.2 pg\/ml after naloxone. 3. Naloxone produced a transient increase in arterial blood pressure in morphine\u2010treated but not control rats. Concentrations in plasma of vasopressin, measured by radioimmunoassay in samples of femoral arterial blood, rose in morphine\u2010treated rats from 7.4 +\/\u2010 2.4 to 29.2 +\/\u2010 3.7 pg\/ml after naloxone, but did not rise significantly in control rats. 4. Naloxone (1\u20105 mg\/kg) produced a prompt and prolonged increase in the discharge rate of each of ten continuously active (putative oxytocin) cells recorded from ten morphine\u2010treated rats. The discharge rate of the six cells tested at the highest dose (5 mg\/kg) increased by an average of 6.3 Hz (360%) within 5 min, and the firing rate remained elevated for at least 30 min; the discharge rate of six continuously active supraoptic neurones recorded in control rats was not affected by naloxone. 5. The firing activity of five phasic (putative vasopressin) supraoptic neurones in morphine\u2010treated rats was increased for at least 30 min by the injection of naloxone; these increases were the result of a raised intraburst firing rate with no change in burst duration or frequency. One phasic neurone was inhibited for 15 min, and one phasic neurone was unaffected. 6. The excitatory effects of naloxone on neurones in the supraoptic nucleus of morphine\u2010treated rats were not explained by changes in blood pressure or osmolarity and did not depend on suckling or a cholinergic pathway. 7. The concentrations of oxytocin in plasma and the operation of the milk\u2010ejection reflex were similar in the controls and morphine\u2010treated rats, prior to naloxone. These findings indicate tolerance to initial inhibitory effects of morphine on oxytocin secretion.(ABSTRACT TRUNCATED AT 400 WORDS)<\/jats:p>","DOI":"10.1113\/jphysiol.1988.sp016963","type":"journal-article","created":{"date-parts":[[2014,12,19]],"date-time":"2014-12-19T06:35:49Z","timestamp":1418970949000},"page":"297-317","source":"Crossref","is-referenced-by-count":71,"title":["Naloxone excites oxytocin neurones in the supraoptic nucleus of lactating rats after chronic morphine treatment."],"prefix":"10.1113","volume":"396","author":[{"given":"R J","family":"Bicknell","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"G","family":"Leng","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D W","family":"Lincoln","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J A","family":"Russell","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[1988,2]]},"container-title":["The Journal of Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1113%2Fjphysiol.1988.sp016963","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1988.sp016963","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,21]],"date-time":"2023-10-21T11:16:19Z","timestamp":1697886979000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1988.sp016963"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1988,2]]},"references-count":0,"journal-issue":{"issue":"1","published-print":{"date-parts":[[1988,2]]}},"alternative-id":["10.1113\/jphysiol.1988.sp016963"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1988.sp016963","archive":["Portico"],"relation":{},"ISSN":["0022-3751","1469-7793"],"issn-type":[{"value":"0022-3751","type":"print"},{"value":"1469-7793","type":"electronic"}],"subject":[],"published":{"date-parts":[[1988,2]]}}}