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Role of serotonin in opiate-induced prolactin secretion and antinociception in the developing rat.

Publication ,  Journal Article
Bero, LA; Kuhn, CM
Published in: J Pharmacol Exp Ther
March 1987

Our laboratory has demonstrated previously that the ability of opiates to stimulate prolactin (PRL) release during ontogeny precedes the appearance of a PRL response to serotonergic drugs. The present study tests the hypothesis that opiates stimulate PRL secretion through a serotonergic mechanism in adult rats, but a nonserotonergic mechanism in neonatal rats. Morphine stimulated PRL secretion in adult and neonatal (10-day-old) rats and this increase was blocked with the opiate antagonist naloxone. Ten-day-old or adult rats were pretreated with the serotonin antagonist, cyproheptadine (CYPRO), or the neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT). Both CYPRO and 5,7-DHT attenuated the PRL response to morphine in adult but not neonatal rats. 5,7-DHT decreased serotonin and 5-hydroxyindoleacetic acid substantially in the hypothalamus. When rats were pretreated with 5,7-DHT several weeks before morphine challenge, serotonin depletion was more pronounced, but the PRL response to morphine was not decreased. In addition, the PRL response to 5-hydroxytryptophan was greatly potentiated, suggesting that functional supersensitivity developed in the 5,7-DHT-treated animals. The ability of CYPRO and 5,7-DHT to block the serotonergic component of a different morphine-induced behavior in the neonate was tested using the tail immersion test for analgesia. Morphine produced profound antinociception in the rat pup which was attenuated markedly by 5,7-DHT and CYPRO. These studies demonstrate that opiates mediate their stimulatory effects on PRL release, at least in part, through a serotonergic mechanism in adult rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Duke Scholars

Published In

J Pharmacol Exp Ther

ISSN

0022-3565

Publication Date

March 1987

Volume

240

Issue

3

Start / End Page

831 / 836

Location

United States

Related Subject Headings

  • Serotonin
  • Rats, Inbred Strains
  • Rats
  • Prolactin
  • Pharmacology & Pharmacy
  • Pain
  • Morphine
  • Hypothalamus
  • Hydroxyindoleacetic Acid
  • Cyproheptadine
 

Citation

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Bero, L. A., & Kuhn, C. M. (1987). Role of serotonin in opiate-induced prolactin secretion and antinociception in the developing rat. J Pharmacol Exp Ther, 240(3), 831–836.
Bero, L. A., and C. M. Kuhn. “Role of serotonin in opiate-induced prolactin secretion and antinociception in the developing rat.J Pharmacol Exp Ther 240, no. 3 (March 1987): 831–36.
Bero, L. A., and C. M. Kuhn. “Role of serotonin in opiate-induced prolactin secretion and antinociception in the developing rat.J Pharmacol Exp Ther, vol. 240, no. 3, Mar. 1987, pp. 831–36.
Bero LA, Kuhn CM. Role of serotonin in opiate-induced prolactin secretion and antinociception in the developing rat. J Pharmacol Exp Ther. 1987 Mar;240(3):831–836.

Published In

J Pharmacol Exp Ther

ISSN

0022-3565

Publication Date

March 1987

Volume

240

Issue

3

Start / End Page

831 / 836

Location

United States

Related Subject Headings

  • Serotonin
  • Rats, Inbred Strains
  • Rats
  • Prolactin
  • Pharmacology & Pharmacy
  • Pain
  • Morphine
  • Hypothalamus
  • Hydroxyindoleacetic Acid
  • Cyproheptadine