title: Calretinin and somatostatin immunoreactivities label different human submucosal neuron populations.
abstract: In human myenteric plexus, calretinin (CALR) and somatostatin (SOM) coexist in Dogiel Type II neurons, which were considered as intrinsic primary afferent neurons in the guinea pig. The aims of this study were to test if also human submucosal neurons costain immunohistochemically for CALR and SOM and whether these or other neurons display Type II morphology. Two sets of submucosal wholemounts of small and large intestine from 29 patients (median age 65 years) were triple stained for CALR, SOM, and human neuronal protein Hu C/D (HU, a pan-neuronal marker) as well as for CALR, SOM, and peripherin (PER), respectively. Only exceptionally, neurons coreactive for both CALR and SOM were found. The three major groups of neurons were CALR-/HU-coreactive (CALR-neurons), SOM-/HU-coreactive (SOM-neurons), and HU-alone-positive neurons. We observed significantly more CALR-neurons in the external submucosal plexus (ESP) of all regions and more SOM-neurons in the internal submucosal plexus (ISP), although with substantial interindividual variations. Comparisons of small vs. large intestine revealed more SOM-neurons (ESP: 29% vs. 4%, ISP: 40% vs. 13%) but fewer CALR-neurons (ESP: 37% vs. 77%, ISP: 21% vs. 67%) in small intestine. Morphologically, CALR-neurons had multiple processes; in some cases, we identified multidendritic/uniaxonal neurons. In contrast, SOM-neurons had mostly only one process. The functions of both populations as possible primary afferent neurons, interneurons, secretomotor neurons, or vasomotor neurons are discussed. Future morphochemical distinction of these groups may reveal different subgroups.
authors.affiliation: Institute of Anatomy I, Erlangen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kustermann
authors.forename: Winfried
authors.initials: W
authors.lastname: Neuhuber
authors.forename: Axel
authors.initials: A
authors.lastname: Brehmer
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D064032:Calbindin 2; D002648:Child; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D007381:Intermediate Filament Proteins / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D008875:Middle Aged; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D064531:Peripherins; D064030:S100 Calcium Binding Protein G / Q000276:immunology / Q000378:metabolism*; D013004:Somatostatin / Q000276:immunology / Q000378:metabolism*; D013368:Submucous Plexus / Q000378:metabolism*; D055815:Young Adult
chemical_list: C576764:CALB2 protein, human; D064032:Calbindin 2; D007381:Intermediate Filament Proteins; D008562:Membrane Glycoproteins; D009419:Nerve Tissue Proteins; C578994:PRPH protein, human; D064531:Peripherins; D064030:S100 Calcium Binding Protein G; D013004:Somatostatin