title: Plasma beta-endorphin concentration and xanthine treatment in apnea of prematurity.
abstract: Apnea of prematurity is a common problem in neonatal intensive care nurseries. Xanthines are used to treat apnea, but their mechanism of action is not clearly understood. To determine whether xanthines stimulated beta-endorphin (beta-ED) release in preterm infants, plasma beta-ED concentrations were measured in 27 infants with apnea of prematurity. These infants had a mean (+/- SD) birthweight of 1560 +/- 487 g, gestational age 31 +/- 2.5 weeks, and a postnatal age of 7.3 +/- 4.6 d. Twenty-five of the infants were treated with I.V. aminophylline 2.5 mg/kg/dose 4 times daily and 2 were treated orally with caffeine (10 mg/kg). Blood samples were collected prior to and 30 min after treatment with xanthines. Apneic spells greater than 15 sec were recorded and reviewed every 24 h using a Hewlett-Packard Merlin Monitor (Waltham, MA.) system. Infants were then stratified into responders (Group 1, n = 14) and nonresponders (Group 2, n = 13), with responders defined as showing more than 50% decrease in the frequency of apneic spells in the first 24 h of treatment. beta-ED were measured as previously described using a radioimmunoassay technique. In group 1, plasma beta-ED concentration increased significantly, (p = 0.0496) from pre-xanthine (24.4 +/- 12 pg/ml) to post xanthine (34.6 +/- 24 pg/ml) treatment, whereas in Group 2 the concentrations remained the same (23.3 +/- 5 pg/ml) and (22.6 +/- 4 pg/ml). Birthweight, gestational age, postnatal age, and diagnoses in both groups were compared and no significant differences were observed. Interestingly, xanthine treatment caused increased plasma beta-ED release when apneas decreased.
authors.affiliation: Department of Pediatrics, College of Medicine and Pharmacy, University of Saskatchewan, Saskatoon.
authors.forename: K
authors.initials: K
authors.lastname: Sankaran
authors.forename: K W
authors.initials: KW
authors.lastname: Hindmarsh
authors.forename: L
authors.initials: L
authors.lastname: Tan
authors.forename: M
authors.initials: M
authors.lastname: Kalapurackal
mesh_terms: D001049:Apnea / Q000097:blood* / Q000188:drug therapy*; D002110:Caffeine / Q000494:pharmacology; D006801:Humans; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000097:blood* / Q000188:drug therapy*; D019820:Xanthine; D014970:Xanthines / Q000627:therapeutic use*; D001615:beta-Endorphin / Q000097:blood*
chemical_list: D014970:Xanthines; D019820:Xanthine; D002110:Caffeine; D001615:beta-Endorphin