Growth-associated Protein-43 (GAP-43) Expression In Ganglionic and Aganglionic Colon.

Abstract Objectives: Because of its specificity for nerve fibers of the enteric nervous system, calretinin is an effective adjunctive marker in the assessment for Hirchsprung disease. Growth associated protein (GAP-43) has been shown to be expressed in nerve fibers within the intestinal lamina propria. No prior report compares GAP-43 expression in ganglionic versus aganglionic intestine. Methods: Six consecutive Hirschsprung endorectal pull through specimens were retrieved from our archives. In addition 3 controls were selected from colonic resections for reasons other than Hirschsprung Disease. Immunoperoxidase for GAP-43 was carried out on the ganglionic and aganglionic segments of all cases and controls. Submucosal ganglion soma positivity and nerve fiber positivity within the lamina propria were graded on a subjective scale of 1-3 that incorporated both strength and density. Data: GAP-43 strongly stained submucosal ganglion cells and nerve fibers within the lamina propria in 6/6 of the ganglionic segments and 3/3 of the normally innervated controls . GAP-43 did not show any ganglion cell body positivity within the aganglionic segments; however, all 6 aganglionic segment lamina propria were positive for nerve fiber staining. There was a small subjective increase in the amount of nerve fiber positivity for GAP-43 in ganglionic segments and controls versus aganglionic segments. Conclusion: GAP-43 marks mucosal nerve fibers in ganglionic intestine but also aganglionic intestine and thus is less useful than calretinin as a marker for Hirschsprung Disease. The abundant mucosal nerves highlighted by GAP-43 requires further characterization.

Glomerular nucleus of the weakly electric fish, Gymnotus sp.: cytoarchitecture, histochemistry, and fiber connections--inisights from neuroanatomy to evolution and behavior.

The present study provides a detailed description of morphological and hodological aspects of the glomerular nucleus in the weakly electric fish Gymnotus sp., and explores the evolutionary and functional implications flowing from this analysis. The glomerular nucleus of Gymnotus shows numerous morphological similarities with the glomerular nucleus of percomorph fish, although cytoarchitectonically simpler. In addition, congruence of the histochemical acetylcholinesterase (AChE) distribution with cytoarchitectonic data suggests that the glomerular nucleus, together with the ventromedial cell group of the medial subdivision of the preglomerular complex (PGm-vmc) rostrally, and the subglomerular nucleus (as identified by Maler et al. [1991] J Chem Neuroanat 4:1­38) caudally, may form a distinct longitudinally organized glomerular complex. Our results show that an important source of sensory afferents to the glomerular nucleus originates in the pretectal and electrosensorius nuclei. The glomerular nucleus in turn projects to the hypothalamus (inferior lobe and anterior hypothalamus), to the anterior tuberal nucleus, and to the medial region of the preglomerular nucleus (PGm). These data suggest that visual and electrosensory information reach the glomerular nucleus and are relayed to the hypothalamus and, via PGm, to the pallium. Such connections are similar to those of the glomerular nucleus in percomorphs and the posterior pretectal nucleus in osteoglossomorph, esocids, and salmonids, where they comprise one component of a visual processing pathway. In Gymnotiform fish, however, the pretectal region that projects to the glomerular nucleus is dominated by electrosensory input (visual input is minor), which is consistent with the dominant role of electroreception in these fish.

Fiber connections of the diencephalic nucleus tuberis anterior in the weakly electric fish, Gymnotus cf. carapo: an in vivo tract-tracing study.

Transport of biotinylated dextran amine shows the spatial segregation of mechanosensory afferents in the nucleus tuberis anterior (TA) of a gymnotiform fish, Gymnotus cf. carapo. Only the intermediate subdivision of this nucleus receives projections from the lateral region of the ventral torus semicircularis (TSv), which represents the principal midbrain center for mechanosensory information processing, and from the ventral nucleus praeeminentialis, which receives collaterals of ascending second order mechanosensory fibers that emerge from the mechanosensory lateral line lobe. Considering this aspect, a rostrocaudal subdivision of the TA is proposed. The TA also receives input from regions subserving other sensory modalities, suggesting a role in multisensory interaction. Another important finding of this work consisted in the demonstration of reciprocal connections between the TA and the inferior lobe of the hypothalamus, which is known to receive gustatory, visual, and electrosensory input and is therefore considered a multisensory integration center involved in feeding and aggressive behavior. Furthermore, reciprocal connections between the TA and the preelectromotor central-posterior/prepacemaker complex may provide an access for the processed mechanosensory information to interact with the transient modulations of the electric organ discharge that accompany different behaviors.