Effects of opiates on brain development

R. P. Hammer, A. A. Ricalde, J. V. Seatriz

Research output: Contribution to journalArticlepeer-review

91 Scopus citations


Perinatal morphine administration affects neuronal growth in the developing animal. Neuronal packing density was reduced by morphine treatment in both primary somatosensory cortex and preoptic area of the hypothalamus. However, glial packing density was increased, but only in hypothalamus, which could reflect greater severity of opiate-induced neurotoxicity in hypothalamus. Cortical pyramidal neurons show morphine-induced reduction of basilar dendritic growth limited to late-developing terminal branches. This effect is completely reversed by concurrent naltrexone administration. This selective effect could be caused by morphine acting at opiate receptors to inhibit extrinsic determinants of dentritic growth (e.g., afferent supply). The ontogeny of opiate receptors is also affected by perinatal morphine administration in a regionally-dependent manner. Mu-receptors are downregulated by morphine in hypothalamus, but not in cortex. Differential maturity of receptors in these regions could be a factor in such differential drug effects. Therefore, different critical periods for opiate action in different regions of the developing brain could exist.

Original languageEnglish (US)
Pages (from-to)475-484
Number of pages10
Issue number3
StatePublished - 1989


  • cell packing density
  • cerebral cortex
  • morphine
  • opiate receptors
  • preoptic area

ASJC Scopus subject areas

  • General Neuroscience
  • Toxicology


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