{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,4]],"date-time":"2026-05-04T03:51:20Z","timestamp":1777866680409,"version":"3.51.4"},"reference-count":0,"publisher":"S. Karger AG","license":[{"start":{"date-parts":[[2017,8,11]],"date-time":"2017-08-11T00:00:00Z","timestamp":1502409600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"},{"start":{"date-parts":[[2017,8,11]],"date-time":"2017-08-11T00:00:00Z","timestamp":1502409600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/karger.com\/pages\/terms-and-conditions"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Dev Pharmacol Ther"],"abstract":"<jats:p>The effect of endogenous opioid peptide blockade with naloxone on the plasma\ncatecholamine response to asphyxia (hypoxemia + acidemia) was investigated in 6 chronically\ncatheterized late gestation (\u2265120 days) fetal lambs in utero. Animals were assigned\nrandomly to receive either naloxone ( 1 mg\/kg) or saline on alternate days. Hypoxemia was\nproduced by gradual umbilical cord compression until arterial PO(2) &lt;15 Torr and maintained\nfor 15 min. This resulted in the development of acidemia as pH decreased from a\nbaseline of 7.41 \u00b1 0.02 to 7.25 \u00b1 0.01. Fetal heart rate declined initially from 183 \u00b1 5 to\n113 \u00b1 7 beats\/min and then increased progressively to approach, but not return, to baseline,\nwhereas mean arterial pressure continued to rise from 45 \u00b1 2 Torr throughout the 15-min\nobservation period to a peak of 61 \u00b1 5 Torr. No difference was noted between control and\nnaloxone-treated fetuses in their blood pH, PO(2), PCO(2), heart rate or blood pressure\nresponses to asphyxia. Plasma epinephrine concentrations increased 10-fold from 143 \u00b1 45\nto 1391 \u00b1 290 pg\/ml in control fetuses and from 254 \u00b1 58 to 6944 \u00b1 847 pg\/ml, a 27-fold\nincrease, in naloxone-treated fetuses (p &lt; 0.05). Norepinephrine levels were not significantly\naltered by opioid receptor blockade, increasing from 525 \u00b1 121 to 4138 \u00b1 912 pg\/ml in\ncontrols and from 719 \u00b1 186 to 6,958 \u00b1 1,439 pg\/ml in naloxone-treated animals. Thus,\nnaloxone potentiates the plasma epinephrine response to asphyxia. Endogenous opioid peptides\nmay act as modulators of the sympathoadrenal response to severe stress in the fetus.<\/jats:p>","DOI":"10.1159\/000457692","type":"journal-article","created":{"date-parts":[[2017,8,11]],"date-time":"2017-08-11T17:08:51Z","timestamp":1502471331000},"page":"219-225","source":"Crossref","is-referenced-by-count":4,"title":["Naloxone Potentiates the Plasma Catecholamine Response to\nAsphyxia in the Fetus"],"prefix":"10.1159","author":[{"given":"Alan B.","family":"Lewis","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mahvash","family":"Sadeghi","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"127","published-online":{"date-parts":[[2017,8,11]]},"container-title":["Developmental Pharmacology and Therapeutics"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/karger.com\/article-pdf\/doi\/10.1159\/000457692","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,30]],"date-time":"2026-04-30T09:09:13Z","timestamp":1777540153000},"score":1,"resource":{"primary":{"URL":"https:\/\/karger.com\/article\/doi\/10.1159\/000457692"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,8,11]]},"references-count":0,"URL":"https:\/\/doi.org\/10.1159\/000457692","archive":["Portico"],"relation":{},"ISSN":["0379-8305","2504-2505"],"issn-type":[{"value":"0379-8305","type":"print"},{"value":"2504-2505","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,8,11]]}}}