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In the pachymeninx (dura mater) from human spinal cord and brain, expression of mRNA for the beta-trace protein (beta-trace) was studied by in situ hybridization with digoxigenin-labeled cRNA probes. The localization of the protein was investigated using monoclonal and polyclonal antibodies, respectively. Very strong hybridization signals were observed in the fibroblasts of the pachymeninx. The results obtained by in situ hybridization were essentially confirmed by immunocytochemistry. By immunoblotting of proteins solubilized from the dura mater, strong immunoreactions were found with a polyclonal beta-trace antibody. Furthermore, beta-trace was quantified in human ventricular and lumbar cerebrospinal fluid (CSF) by use of an immunonephelometric assay. The beta-trace concentration in human lumbar CSF was elevated 11-fold as compared with ventricular CSF. Beta-trace determined in lumbar CSF most probably originates from fibroblasts of the pachymeninx. According to the bi- or probably multifunctional features of beta-trace, various sites of mRNA expression and protein synthesis exist in the human central nervous system (CNS). The major ones are the fibroblasts of the pachymeninx, and as previously shown, the epithelial layer of the choroid plexus.

The aim of this study was to investigate the neurochemical coding of myenteric neurons in the guinea pig gastric corpus by using immunohistochemical methods. Antibodies and antisera against calbindin (CALB), calretinin (CALRET), choline acetyltransferase (ChAT), calcitonin gene-related peptide (CGRP), dopamine beta-hydroxylase (DBH), beta-endorphin (ENK), neuropeptide Y (NPY), neuron-specific enolase (NSE), nitric oxide synthase (NOS), protein gene product 9.5 (PGP), parvalbumin (PARV), serotonin (5-HT), somatostatin (SOM), substance P (SP), tyrosine hydroxylase (TH), and vasoactive intestinal peptide (VIP) were used. Double- and triple-labeling studies revealed colocalization of certain transmitters and enabled the identification of distinct subpopulations of gastric enteric neurons. NPY/VIP/NOS/ENK were present in 28% of all neurons, whereas 11% had NPY/VIP/DBH/ChAT; NOS-only neurons made up 2% of the population. The combination SP/ChAT/ENK occurred in 21% of the population, whereas SP/ChAT/ENK/CALRET and SP/CHAT/SOM/ +/- CALRET was identified in 5% and 6% of all cells, respectively. 5-HT-containing neurons comprised 2% of all cells and could be further classified by the presence of additional antigens as 5-HT/SP/(ChAT) or 5-HT/VIP/(ChAT). Approximately 21% of all neurons contained only ChAT with no additional antigen present and are referred to as ChAT/-. Gastric myenteric ganglion cells were not immunoreactive for CALB, PARV, CGRP, or TH. The results of this study indicate that gastric myenteric neurons can be characterized on the basis of different chemical coding. Neurochemical coding of corpus myenteric neurons revealed some similarities and significant differences in comparison with other regions of the gut. These differences might reflect adaptation of enteric nerves according to regional specialization and the distinct functions of the proximal stomach as a gastric reservoir.

Choline acetyltransferase (ChAT) from porcine brain was purified by immunoaffinity chromatography, and the highly purified enzyme was subsequently used for immunization of mice and rabbits. After fusion of mouse spleen cells, 32 cultures producing monoclonal antibodies directed against ChAT were detected by an enzyme-linked immu-nosorbent assay (ELISA) with immunoaffinity-purified ChAT. Of these original 32, the most active 11 cultures were cloned and used for ascites production. The 11 clones generated monoclonal antibodies of the immunoglobulin (Ig) M class (three), the IgGl subclass (seven), and the IgG2b subclass (one). The isoelectric points of the antibodies of the IgG class were different in each case. The monoclonal antibodies exhibited different binding characteristics in the above ELISA and on western blots. Two monoclonal antibodies demonstrated excellent immunohistological results with neurons of rat brain and spinal cord. One of them reacted well immu-nohistochemically with neurons of human brain and also recognized partially purified human placenta ChAT in the ELISA.