Analysis of trophic responses in lesioned brain: focus on basic fibroblast growth factor mechanisms

The actions of fibroblast growth factors (FGFs), particularly the basic from (bFGF), have been described in a large number of cells and include mitogenicity, angiogenicity and wound repair. The present review discusses the presence of the bFGF protein and messenger RNA as well as the presence of the FGF receptor messenger RNA in the rodent brain by means of semiquantitative radioactive in situ hybridization in combination with immunohistochemistry. Chemical and mechanical injuries to the brain trigger a reduction in neurotransmitter synthesis and neuronal death which are accompanied by astroglial reaction. The altered synthesis of bFGF following brain lesions or stimulation was analyzed. Lesions of the central nervous system trigger bFGF gene expression by neurons and/or activated astrocytes, depending on the type of lesion and time post-manipulation. The changes in bFGF messenger RNA are frequently accompanied by a subsequente increase of bFGF immunoreactivity in astrocytes in the lesioned pathway. The reactive astrocytes and injured neurons synthesize increased amount of bFGF, which may act as a paracrine/autocrine factor, protecting neurons from death and also stimulating neuronal plasticity and tissue repair.

Myenteric neurons of the mouse small intestine. Morphometry and acetylcholinesterase activity

1. The myenteric plexus of the small intestine of five C57BL/6J male 5-month-old mice was investigated in whole-mount preparations of the muscularis externa by Giemsa staining and by the acetylcholinesterase (AChE) histochemical technique. 2. The neuronal density was 20212 ñ 3038/cm² (mean ñ SEM) in the duodenum, 21948 ñ 1488/cm² in the jejunum, 25048 ñ 2356/cm² in the ilium. The difference in neuronal density between duodenum and ileum was statistically significant (P<0,05). The total serosal surface area of the small intestine was about 30.80 ñ 2.90 cm², and the total number of neurons was estimated at about 690,000. 3. The neuronal cell and nucleus profile areas ranged, respectively, from 23 to 325 µm² and from 6 to 95 µm² in the small intestine of the mice studied. There were no significant differences in any of the 3 regions in terms of average neuronal cell or nucleus profile areas. 4. For the histochemical demonstration of AChE, the "direct coloring" copper ferrocyanide method was used. AChE-positive nerve fibers were distributed in the myenteric plexus which was formed by a primary meshwork of relatively large nerve bundles and a secondary meshwork of finer nerve bundles. Most of the neurons of the plexus displayed AChE activity in the cytoplasm though the neurons presented different reaction intensities. 5. The results of the present study show that the myenteric plexus of the C57BL/6J mouse small intestine contains a large number of neurons which have different sizes and AChE activities

Number, size and distribution of ganglion neurons in urinary bladder of rodents

Whole-mount preparations of urinary bladders stained with a modified Giemsa technique were obtained from three rodent species (Guinea-pig, Calomys callosus and the C57/BLJ isogenic mouse) to identify andestimate the relative number and size of ganglionic neurons within the wall of the organ. The istribution of the ganglia was not uniform among the three species: ganglia were concentrated around the ureteral orifices in the Guinea-pig, they were scattered throughout the organ in Calomys callosus, and they were oncentrated near the internal urethral orifice in the C57/BLJ mouse. In the Guinea-pig, the size of approximately 50 percent of the neurons lie in the range of 200 to 300 microns2. In Calomys callosus, 40 percent of the neurons lie in the range of 200 to 250 microns2, with 28 percnet in the range of 50 to 100 microns2. For the C57/BLJ mouse, approximately 60 percent of the neurons have an area of 250 to 400 microns2