Godelieve Vierendeels

Substance P, enkephalins, somatostatin, cholecystokinin, oxytocin, and vasopressin in human spinal cord

Several neuropeptides were immunohistologically studied in normal human spinal cords. Substance P, methionine-enkephalin, leucine-enkephalin, and cholecystokinin positive fibers were found in all cytoarchitectonic layers, with a specific distribution pattern for each peptide. Somatostatin, oxytocin, and vasopressin immunoreactivities were restricted to particular spinal layers. Perikarya and proximal dendrites were visualized and classified by comparison with previous Golgi analyses. Substance P was contained in “radiate cells” of layer III, methionine-enkephalin in marginal neurons as well as in layer II “stellate cells,” and somatostatin in layer II “islet cells.” Several results differed from those reported in other species. Chemical neuroanatomy may provide new insights into the neuronal organization of the human spinal cord.

Study of neuropeptide Y-containing nerve fibers in the human penis

SummaryNeuropeptide Y 1–36 (IR-NPY) immunoreactive nerve-fiber processes have been observed in tunicae of veins and arteries and in smooth muscles of the human penis taken at autopsy or during surgery by use of light-and electron-microscopic immunohistochemical techniques. Numerous IR-NPY nerve fibers were mostly concentrated in the inner part of the adventitia close to the media of the arterial and venous vessels and among the intracavernous smooth muscle cells. IR-NPY nerve fibers were less abundant in veins than in arteries. Positive somata were not observed in the penises. At the ultrastructural level, IR-NPY were localized exclusively in large, dense granules of nerve terminals by means of the postembedding immunogold technique. In the deep dorsal vein, IR-NPY nerve fibers were also located in the media formed by an outer circular and an inner longitudinal layer. In the intracavernous and dorsal arteries, they showed the highest density in the inner part of the adventitia. In the corpora cavernosa and in the corpus spongiosum, IR-NPY nerve processes were intermingled between the smooth-muscle fibers around the sinusoid spaces. IR-NPY nerve fibers were present in the cavernous nerves close to the central arteries. The urethra did not show any IR-NPY-positive nerve fibers. This peculiar distribution of IR-NPY nerve fibers suggested that they could participate in regulating arterial and venous blood flow and intracavernous smooth-muscle tone. NPY may therefore be of importance in some of the mechanisms of penile erection especially during detumescence.

Decrease of vasoactive intestinal peptide, methionine-enkephalin, substance P and increase of neuropeptide Y immunoreactive nerve fibres in aganglionic colon of Hirschsprung's disease.

Ganglionic and aganglionic full-thickness samples, at 4 levels of the colon of 26 infants with Hirschsprungs disease, were studied by immunohistochemistry. In the distal part of the aganglionic bowel, we observe a decrease of substance P and vasoactive intestinal peptide, an absence of methionine-enkephalin and an increase in neuropeptide Y nerve fibres. When detected, substance P and vasointestinal peptide are mainly present in abnormal bundle nerve fibres. In the middle part of the aganglionic bowel, a slight increase in the number of normal nerve fibres containing substance P, methionine-enkephalin and vasoactive intestinal peptide is observed. Some vasoactive intestinal peptide abnormal bundle nerve fibres are detected. They are less numerous than in the distal part. In the proximal ganglionic bowel, the number of vasoactive intestinal peptide, substance P and methionine-enkephalin normal nerve fibres is increased compared to the middle aganglionic segment but is slightly lower than in the normal colon. Again vasoactive intestinal peptide abnormal bundle nerve fibres are present at that level and are also detected in more proximal ganglionic bowel up to the hepatic flexure of the colon. Thus, abnormal distribution of neuropeptides is also found in more proximal ganglionic bowel and not only in the aganglionic segment of bowel usually specific of Hirschsprungs disease.

Neurotensin containing neurones in the human hippocampus of the adult and during development

Marked age-related changes are noted in the neurotensin distribution of the human hippocampus. Different neuronal structures containing neurotensin are detected by immunohistochemistry during postnatal brain growth from birth to 4 years but no later. They are the neurotensin-immunoreactive pyramidal cells of the subiculum and presubiculum. Their axonal fibres are seen in the alveus and the fimbria. There are also the neurotensin-immunoreactive granular cells of the hilus. The varicosities of the mossy fibres are detected among the pyramidal cells of the CA3 and CA2 subfields of the Ammons horn. After 4 years of age, only the varicosities are shown by immunohistochemistry, thus there is probably an important decrease in the neurotensin concentration in the cell bodies of the granular cells and also in the pyramidal neurons of the subiculum and presubiculum.

High concentration of somatostatin-14 neurones in the infant human hippocampus.

The distribution of somatostatin-14 immunoreactivity (SRIF-14-IR) was studied in the hippocampal formation of the human infant. The most prominent accumulation of SRIF-14-IR cell bodies and processes occurred in the CA1 subfield of the stratum oriens in the Ammons horn, in the hilus of the area dentata, in the deeper layers of the subicular complex and in the entorhinal cortex. SRIF-14-IR neurones are also detected in the angular bundle though they are rare in the alveus and absent in the fimbria.

Proenkephalin A associated peptides in the autonomic nervous system of the human infant gastrointestinal tract.

The digestive tract of neonates and infants were examined by immunohistochemistry using specific antisera raised against proenkephalin A related peptides. Proenkephalin A, methionine-enkephalin and leucine-enkephalin are observed in nerve fibres in the smooth muscles in the myenteric and submucosal plexuses or in neuronal cell bodies of the myenteric plexus. In these structures synenkephalin has general distribution as methionine-enkephalin but not the same as leucine-enkephalin. Co-localization of synenkephalin and methionine-enkephalin is found in several neurones. These results suggest that proenkephalin A is the precursor-protein in some enkephalinergic neurones of the human gut. A gradient in the density of immunoreactivity is observed and is maximal in the distal small bowel. This gradient contrasts with observations made in rodents where major enkephalin immunoreactivity is observed in the proximal digestive tract. These findings give evidence that proenkephalin A-derived peptides could have effects in the motility of the human gut.

Neuropeptide Y, somatostatin, and cholecystokinin neurone preservation in anaplastic astrocytomas.

SummaryUsing immunohistochemistry, well-preserved neuronal cell bodies and fibres containing neuropeptide Y, somatostatin, and cholecystokinin immunoreactivity have been identified in all seven supratentorial anaplastic astrocytomas studied. These neurones have been shown not only on the edge but also in the depth of the neoplastic tissue. These neuropeptides were not present in 18 other intracranial tumours (3 astrocytomas, 1 subependymoma, 8 glioblastoma multiformes, 1 meningioma, and 5 metastases). In all 25 intracranial tumours studied, no immunoreactivity was found for vasoactive intestinal polypeptide, substance P, methionine-enkephalin, leucine-enkephalin, synenkephalin, neurophysin I-II, and corticotropin releasing factor.