Ontogeny of the striatal neurons expressing neuropeptide genes in the human fetus and neonate

Abstract

The distribution patterns of neurons expressing mRNAs for four neuropeptides in the human striatum were studied during ontogeny by the use of in situ hybridization. The results of our study demonstrate that somatostatin, enkephalin, dynorphin, and substance P mRNAs are present in striatal neuronal populations from week 12 of fetal life. Each neuronal population undergoes a specific differentiation. Neurons containing somatostatin mRNA are scattered throughout the caudate-putamen up until birth. Neurons containing enkephalin, dynorphin, or substance P mRNAs evolve throughout fetal life in relation to caudate-putamen and patch-matrix compartmentalization. Neurons containing enkephalin mRNA (distinct from those containing substance P or dynorphin mRNAs) are present in the matrix from week 12 of fetal life. These neurons are preferentially distributed in the matrix and, at birth, display higher enkephalin mRNA content in the matrix than in the patches. Dynorphin mRNA is found in the caudate and putamen, preferentially in the patch neurons; nevertheless, a low level of dynorphin mRNA is also present in neurons of the caudate matrix. Substance P mRNA is initially restricted to caudate neurons. At birth, both substance P and dynorphin mRNAs are expressed at high levels in the patches. These results demonstrate that each neuropeptide gene is expressed during human fetal life in neurons with a specific topology and pace of development in relation to caudate-putamen and patch-matrix differentiation. These results also contribute evidence that neurochemical evolution of the striatal neuronal populations is not complete at birth in humans.

ACTH silent adenoma shrinking under cabergoline

“…The protocol used has been described previously (6). Briefly, antisense and sense radiolabelled cRNA probes were prepared by in vitro transcription of the DNA template from plasmid pCMV5 constructs containing the cDNA encoding D2 receptor (2300 bp).…”

κ-Opioid Receptor Inhibition of Calcium Oscillations in Spinal Cord Neurons

“…Opioid receptors (KORs) are widely expressed in the CNS and are specifically activated by endogenous opioids derived from prodynorphin (Chavkin et al, 1982). KORs and dynorphin mRNA initially appear during early embryonic development in both mouse and human CNS (Brana et al, 1995;Zhu et al, 1998). Dynorphin has been shown to inhibit excitatory transmission in the CNS either when exogenously applied (Castillo et al, 1996;Simmons and Chavkin, 1996;Iremonger and Bains, 2009) or endogenously released (Wagner et al, 1993;Iremonger and Bains, 2009).…”

Discrete opioid gene expression impairment in the human fetal brain associated with maternal marijuana use

“…Preproenkephalin is primarily expressed in striatal medium spiny projection neurons which comprise the indirect pathway innervating the globus pallidus, whereas PDYN is primarily expressed in the direct pathway to the substantia nigra. 53 Imbalance of these striatal output circuits is normally related to motor disturbances. Although prenatal marijuana exposure has been associated with increased tremors in newborns, this impairment disappears with increasing age (for a review see 52 ).…”

“…The PENK and PDYN gene expression had been documented to have a differential expression in the striatal patch and matrix compartment; both genes have a higher expression in the patch vs matrix. 53 Measurements were made separately on the patch (high expressing islands) and matrix compartment (low expressing surrounding area) by setting a threshold in optical density. The region with optical density above threshold was measured as patch and below as matrix compartment.…”