{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,1]],"date-time":"2025-12-01T11:15:23Z","timestamp":1764587723359},"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. Acutely, opioids inhibit oxytocin secretion. To study the responses of oxytocin neurones during chronic opioid exposure, forty\u2010five lactating rats were infused continuously from a subcutaneous osmotically driven mini\u2010pump via a lateral cerebral ventricle with morphine sulphate solution from day 2 post\u2010partum for 5\u20107 days; the infusion rate was increased 2\u2010 or 2.5\u2010fold each 40 h from 10 micrograms\/h initially up to 50 micrograms\/h; controls were infused with vehicle (1 microliter\/h, twenty\u2010eight rats) or were untreated (eight rats). 2. Maternal behaviour was disrupted in 27% of the morphine\u2010treated rats; in rats that remained maternal morphine did not affect body weight or water intake but increased rectal temperature by 0.82 +\/\u2010 0.14 degrees C (mean +\/\u2010 S.E.M.) across the first 4 days. 3. Weight gain of the litters of maternal morphine\u2010treated rats was reduced by 32% during 7 days, predominantly in the first day of treatment when milk transfer was also reduced. Observation of pup behaviour during suckling showed decreased frequency of milk ejections on only the second day of morphine treatment. Plasma concentration of prolactin after 6 days was similar in maternal morphine\u2010treated and control rats, but reduced by 90% in non\u2010maternal morphine\u2010treated rats, indicating normal control of prolactin secretion by suckling in morphine\u2010treated rats. 4. Oxytocin and vasopressin contents, measured by radioimmunoassay, in the supraoptic and paraventricular nuclei and in the neurohypophysis were similar between fourteen maternal morphine\u2010treated, twelve vehicle\u2010treated and eight untreated lactating rats; thus exposure to morphine did not involve increased production and storage of oxytocin. 5. Distribution of [3H]morphine infused intracerebroventricularly into six virgin female rats for 6 days was measured by scintillation counting of tissue extracts. Morphine concentration in the hypothalamus and neurohypophysis was 2.7 and 12.8 micrograms\/g, respectively, and in blood plasma 0.75 micrograms\/g. Tolerance was not due to failure of morphine infusion. In addition, naloxone (5 mg\/kg s.c.) provoked typical withdrawal reactions ('wet dog' shakes, defaecation, burrowing) in lactating rats infused with morphine for 5 days. 6. Pups were suckled onto seven maternal morphine\u2010infused and five vehicle\u2010infused rats anaesthetized with urethane for recording of intramammary and arterial blood pressures after treatment for 5 days. The incidence and pattern of milk ejections, and mammary gland sensitivity to oxytocin were similar in the two groups.(ABSTRACT TRUNCATED AT 400 WORDS)<\/jats:p>","DOI":"10.1113\/jphysiol.1988.sp016964","type":"journal-article","created":{"date-parts":[[2014,12,19]],"date-time":"2014-12-19T06:35:49Z","timestamp":1418970949000},"page":"319-347","source":"Crossref","is-referenced-by-count":48,"title":["Chronic intracerebroventricular morphine and lactation in rats: dependence and tolerance in relation to oxytocin neurones."],"prefix":"10.1113","volume":"396","author":[{"given":"V C","family":"Rayner","sequence":"first","affiliation":[]},{"given":"I C","family":"Robinson","sequence":"additional","affiliation":[]},{"given":"J A","family":"Russell","sequence":"additional","affiliation":[]}],"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.sp016964","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/jphysiol.1988.sp016964","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,21]],"date-time":"2023-10-21T11:16:30Z","timestamp":1697886990000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/jphysiol.1988.sp016964"}},"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.sp016964"],"URL":"https:\/\/doi.org\/10.1113\/jphysiol.1988.sp016964","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]]}}}