Ontogeny of somatostatin‐containing neuron system of the rat: Immunohistochemical analysis. II. Forebrain and diencephalon

Abstract

The ontogeny of the somatostatin (SRIF) neuron system in the forebrain and diencephalon the rat was investigated by means of the indirect immunofluorescence method. SRIF-positive cells first appear in the primordium of the hypothalamus surrounding the fasciculus mammillothalamicus of the fetus at gestational day 14 (10-12-mm embryo). At gestational days 16-17 (14-17-mm embryo, SRIF-positive cells appear in the developing piriform cortex and entopeduncular nucleus. The fetus at gestational days 18-19 (17-26-mm embryos) showed a remarkable increase in the number of SRIF-positive cells and numerous groups of such cells are detectable in various forebrain and diencephalic areas such as the hypothalamic periventricular zone, zona incerta, area lateral to the commissura posterior (ACP), area between the optic tract and capsula interna, pars retrolenticularis (AOR), n. caudatus putamen, hippocampus, somatic sensory cortex, and n. accumbens, etc. At gestational day 20, SRIF-positive cells newly appear in the septum, olfactory bulb, diagonal band of Broca, claustrum, lateral preoptic area, and lateral habenular nucleus. The majority of SRIF-positive structures found in the forebrain and diencephalon increase in number during the perinatal stage (between gestational day 21 and postnatal day 2) and more or less maintain their immunoreactivity even in adult rats. However, SRIF-positive cells located in the AOR, ACP, and lateral septal area, etc., begin to decrease in number during the perinatal stage and no or only a few SRIF-containing cells are identified in these areas of infant and adult rats.

Molecular characterization and expression of three preprosomatostatin genes and their association with growth in common carp (Cyprinus carpio)

“…It has been reported that SS may participate in the differentiation and development of tissues (Wang et al, 1995). During development of the forebrain and diencephalon in mouse, SRIF-positive cells first appear in the primordium of the hypothalamus at gestational day 14, then remarkably increase in number in various forebrain and diencephalic areas at gestational days 18-19, and sequentially increase in number during the perinatal stage (Shiosaka et al, 1982). Furthermore, preproCST reaches a maximum level in the cortical areas of mouse during the second post-natal week, which correlates with the maturation of cortical interneurons (de Lecea et al, 1997).…”

Differential Regulation of Basal and Cyclic Adenosine 3',5'-Monophosphate-Induced Somatostatin Gene Transcription in Neural Cells by DNA Control Elements That Bind Homeodomain Proteins

“…During development, somatostatin-expressing cells in the central nervous system appear first in the primordium of the E14 hypothalamus, and other telencephalic regions are recruited later (12,13,15,16). As the central nervous system develops, somatostatin is expressed in differentiating neurons as well as in glial cells, but the number of somatostatin-positive cells fluctuates.…”

“…Primary cultures of cells from developing cerebral cortex and hippocampus, two brain regions that contain somatostatinproducing neurons (12), were prepared from E16 fetuses removed from timed-pregnant Sprague Dawley rats. After careful removal of the meningeal membranes, the cerebral cortex was separated from the rest of the brain, and the developing hippocampi were dissected as described (58).…”

“…In the rat, the first somatostatin-positive cells in the forebrain appear at embryonic day 14 (E14) (12,13). In some cells, this expression is transient, whereas in others it is maintained in the adult brain, and thus it has been proposed that in addition to its role as a neurotransmitter, somatostatin may have trophic effects on target cells during brain development (14)(15)(16).…”

Ontogeny of neuropeptides in the rat brain: An immunohistochemical analysis.

“…On the other hand, no NTI cells were noted in the vm at any of the stages examined. Somatostatin-like immunoreactive (SOMI) structures : SOMI fibers appeared first in vm at gestational day 19 (21). At this stage, a few SOMI cells were seen around the vm but not within the vm.…”