Biomedical subjects

S J Gibson

Publications and source records attributed to S J Gibson.

At least 73 records · Page 4Linked to original sources

PubMed1988

Calcitonin gene-related peptide messenger RNA is expressed in sensory neurones of the dorsal root ganglia and also in spinal motoneurones in man and rat.

Calcitonin gene-related peptide (CGRP) mRNA was localised to neurones of the dorsal root ganglia and motoneurones of the ventral horn in man and rat. Presence of alpha- and beta-CGRP mRNA was confirmed by Northern blot analysis of rat tissues which showed alpha-CGRP was the predominant gene. The distribution of CGRP gene transcripts corresponded with neurones displaying CGRP immunoreactivity in the ganglia of both species and in the rat ventral horn. In man few motoneurones were immunoreactive despite many expressing CGRP mRNA. In situ hybridisation revealed not only sensory but also motor neurones are sites of CGRP manufacture. Thus in conjunction with other evidence the present study reinforces the proposed muscle trophic role for this peptide.

Aged↗

PubMed1988

Ultrastructural studies on calcitonin gene-related peptide-, tachykinins- and somatostatin-immunoreactive neurones in rat dorsal root ganglia: evidence for the colocalization of different peptides in single secretory granules.

Calcitonin gene-related peptide (CGRP)-, tachykinins- and somatostatin-immunoreactive neurones in rat dorsal root ganglia have been studied by means of single and double immunogold labelling techniques. Peptide-immunoreactive neurones are generally B- or C-type cells of small size, with well developed rough endoplasmic reticulum and scanty neurofilaments. In neurones classifiable as A2-type cells, i.e. larger neurones with a lighter cytoplasm due to the presence of poorly developed Nissl bodies and numerous neurofilaments, only CGRP immunoreactivity was detected. Immunolabelled structures were identified as large (60-100 nm diameter), electron-dense, membrane-bounded p-type granules. They were observed only in neuronal cell bodies or in the intraganglionic portions of the axons. No granules immunoreactive to the antisera applied in this study were observed in non-neuronal cells. Immuno-staining experiments with different combinations of the antisera revealed, in some cells, the presence of double immunolabelled granules; in particular localization of CGRP and tachykinins, CGRP and somatostatin, and tachykinins and somatostatin to single secretory granules was demonstrated. The finding that more than one peptide is localized to the same secretory granule supports the postulate that peptides are co-released upon nerve stimulation providing morphological support for physiological and pharmacological data demonstrating an interaction between different peptides in the modulation of synaptic activity.

Animals↗

PubMed1988

Occurrence and developmental pattern of neuromedin U-immunoreactive nerves in the gastrointestinal tract and brain of the rat.

Neuromedin U is a newly described regulatory peptide, found by radioimmunoassay in significant concentrations in both the brain and gut of the rat. The aim of the present study was to localize this peptide immunoreactivity to discrete structures of the gut and brain and to map its distribution using immunocytochemistry. In the gut, neuromedin U was confined to nerve fibres mainly in the myenteric and submucous plexuses and the mucosa of all areas except stomach. Immunoreactive ganglion cells were seen in both ganglionated plexuses and their number did not increase following colchicine administration. This observation and the finding that the population of neuromedin U-immunoreactive nerves in the ileum was not affected by complete extrinsic denervation indicated that the nerves are mostly intrinsic in origin. Colocalization studies revealed neuromedin U and calcitonin gene-related peptide were present in the same myenteric and submucosal ganglion cells. Transection experiments showed that, like calcitonin gene-related peptide-immunoreactive nerves, fibres containing neuromedin U project for very short distances in both an oral and anal direction. At the electron microscopic level, neuromedin U immunoreactivity, demonstrated using the immunogold technique, was localized to large granular vesicles. In the central nervous system, neuromedin U immunoreactivity was localized to fibres which were widespread throughout the brain, except in the cerebellum. The presence of neuromedin U-immunoreactive cell bodies was restricted to the rostrocaudal part of the arcuate nucleus. Colocalization studies showed that a proportion of the neuromedin U-immunoreactive cell bodies in the arcuate nucleus also contained pro-opiomelanocortin. Neuromedin U-immunoreactive fibres were first detected in the rat intestinal mucosa at day 1 after birth. In the brain, the arcuate nucleus showed neuromedin U-immunoreactive neuronal cell bodies at E16 but not at E14. In conclusion, neuromedin U is a new member of the group of molecules known as brain-gut peptides.

Aging↗

PubMed1988

Localization of 7B2, neuromedin B, and neuromedin U in specific cell types of rat, mouse, and human pituitary, in rat hypothalamus, and in 30 human pituitary and extrapituitary tumors.

The distributions of three novel peptides, 7B2, neuromedin B, and neuromedin U, in rat, mouse, and human pituitaries, rat hypothalamus, and 30 human pituitary tumors were investigated with immunocytochemistry. Immunoreactivity for 7B2 was present in rat, mouse, and human gonadotropes, in intermediate lobe cells and posterior lobe nerve fibers in rats and mice, in rat hypothalamus (particularly in the median eminence), and in eight human pituitary gonadotropinomas. In gonadectomized rats, larger, more numerous LH beta- and 7B2-immunoreactive gonadotropes were seen than in controls. Extractable 7B2-like immunoreactivity was elevated but not significantly so in gonadectomized rat pituitaries [males: castrated, 37.4 +/- 4.3 (mean +/- SE); controls, 26.9 +/- 4.3; females: ovariectomized, 27.2 +/- 2.7; controls, 19.1 +/- 2.2 pmol/gland]. Neuromedin B immunoreactivity was found in normal rat and mouse thyrotropes and weakly in "thyroidectomy" cells in hypothyroid rats, in which extractable pituitary neuromedin B was significantly depleted (thyroidectomized, 87.0 +/- 14.0; methimazole-treated, 82.0 +/- 11.4; control, 230.7 +/- 25.6 fmol/gland). Hyperthyroid rat pituitaries showed increased TSH beta and neuromedin B immunoreactivities and neuromedin B content (TRH-treated, 385.2 +/- 30.2; T4-treated, 352.6 +/- 20.2; control, 230.7 +/- 25.6 fmol/gland). Neuromedin U immunoreactivity occurred in corticotropes of all species, in rat and mouse intermediate lobe, and throughout the rat hypothalamus, with immunoreactive cell bodies in the arcuate nucleus. Neuromedin U-immunoreactive cells were present in six of six human pituitary and five of six human extrapituitary corticotropinomas. In adrenalectomized rats, corticotropes were larger and more numerous than in controls, but extractable anterior pituitary neuromedin U-like immunoreactivity was not raised (adrenalectomized, 3.30 +/- 0.45; control, 3.32 +/- 0.27 pmol/gland). Our findings suggest that 7B2, neuromedin B, and neuromedin U may be involved in pituitary function.

Animals↗

PubMed1987

Ontogeny of peptide- and amine-containing neurones in motor, sensory, and autonomic regions of rat and human spinal cord, dorsal root ganglia, and rat skin.

The developmental patterns of neurofilament triplet proteins, peptide and amine immunoreactivities were compared in motor (ventral spinal cord), sensory (dorsal spinal cord, dorsal root ganglia, epidermis), and autonomic (intermediolateral cell columns, dermis) regions in the rat and human. In the rat, neurofilament triplet proteins first appeared in motoneurones (embryonic day 13). In the youngest human fetuses studied (6 weeks), immunoreactivity was present throughout the spinal cord. Peptides and amines occurred later. Calcitonin gene-related peptide, galanin, somatostatin, neuropeptide Y and its C-flanking peptide (CPON) were the first to appear localized to motoneurones (embryonic days 15-17 rat; fetal weeks 6-14 human). Numbers of immunoreactive motoneurones decreased toward birth, but immunoreactive fibers increased in the ventral horn with enkephalin, thyrotrophin-releasing hormone, and the monoaminergic markers 5-hydroxytryptamine and tyrosine hydroxylase (all presumably of supraspinal origin) the last to appear perinatally. In the dorsal horn, particularly in the rat, a transient expression of substance P-, somatostatin-, and neuropeptide Y/CPON-immunoreactive cells was detected (embryonic days 15-17). A pronounced increase of calcitonin gene-related peptide-, galanin-, somatostatin- and substance P- immunoreactive fibers was found perinatally in both species. This coincided with an increased detection of cells in the dorsal root ganglia containing these peptides and the earliest appearance of calcitonin gene-related peptide-, somatostatin-, and substance P-immunoreactive fibers in the rat epidermis. Few antigens were localized to the intermediolateral cell columns before embryonic day 20 (rat), fetal week 20 (human), with thyrotrophin-releasing hormone-, 5-hydroxytryptamine-, tyrosine hydroxylase-, and vasoactive intestinal polypeptide-immunoreactive nerves appearing perinatally. In the rat dermis, tyrosine hydroxylase-immunoreactive fibers (sympathetic fibers) and fibers immunoreactive for neuropeptide Y/CPON and vasoactive intestinal polypeptide were detected from postnatal day 1. In conclusion, 1) peptide and amine immunoreactivity develops in motor before sensory or autonomic regions, 2) many peptide-containing cells are transient in fetal life, and 3) central terminals of dorsal root ganglion cells express peptides before terminals in the skin.

Animals↗

PubMed1987

Increase of substance P-like immunoreactivity in the peripheral nerve of the axolotl after injury.

That substance P may be a neurotrophic factor in urodele limb regeneration was investigated in the axolotl (Ambystoma mexicanum). Two weeks after section of the peripheral nerves to the forelimb, there was a marked increase in substance P-like immunoreactivity (IR) content of the nerves proximal to the lesion. A smaller increase occurred as early as 3 days after section of nerves innervating a regrowing limb bud (blastema), and substance P-IR fibres were observed by immunocytochemistry to innervate blastema tissue. As substance P-IR by applying capsaicin to peripheral nerve--capsaicin had no effect on substance P-IR in either intact or injured axolotl nerves. Substance P fulfills a number of criteria of a trophic substance in axolotl limb regrowth.

Ambystoma mexicanum↗

PubMed1986

Composition and central projections of the pudendal nerve in the rat investigated by combined peptide immunocytochemistry and retrograde fluorescent labelling.

The central distribution of the afferent and efferent projections of pelvic striated muscles, the pudendal and sciatic nerves, were systemically investigated in rats by retrograde tracing techniques combined with immunocytochemistry using antibodies to 9 neuropeptides. True Blue was injected into either the pelvic muscles, pudendal or sciatic nerves. Seven days later the spinal cord and dorsal root ganglia (L3-S2 levels) were processed for immunocytochemistry. Injection of tracer into the pelvic muscles labelled dorsomedial, ventral and dorsolateral motoneuron groups of the L6 segment and a few sensory neurons in the respective dorsal root ganglia. Pudendal nerve injection also labelled the same motoneuron groups, 50% of neurons of the retrodorsolateral column and numerous sensory neurons of the dorsal root ganglion. Concomitant labelling of pudendal and sciatic nerves with different fluorescent tracers revealed a small number of double-labelled cells in the dorsal root ganglia but only single-labelled cells in the retrodorsolateral nucleus. Enkephalin-, somatostatin- and neuropeptide Y-containing fibres were particularly abundant in and around dorsomedial and dorsolateral groups as well as the intermediolateral cell column. We conclude that in the rat (a) the pudendal nerve has motor, sensory and autonomic (parasympathetic) components in contrast to the sciatic which is primarily motor and somatosensory, (b) some afferents from these nerves exhibit pre-spinal convergence and (c) dorsomedial and dorsolateral motoneuron groups are homologous to Onuf's nucleus in man.

Animals↗

PubMed1986

6-Hydroxydopamine and excitotoxin lesions of medial prefrontal cortex fail to affect schedule-induced drinking in the rat.

Schedule-induced drinking was examined in rats following 6-hydroxydopamine and N-methyl-D-aspartate lesions of the medial prefrontal cortex. 6-Hydroxydopamine reduced the concentrations of dopamine and noradrenaline in the medial prefrontal cortex to 17 and 37% of control values respectively, while changes were not observed in the nucleus accumbens. Lesions with N-methyl-D-aspartate were confined to the medial prefrontal cortex. Schedule-induced water consumption, determined over 11 consecutive 1 h/day testing sessions, was not significantly altered by either lesion. These results suggest that the mesocortical dopaminergic projection to the medial prefrontal cortex, and reciprocal projections from medial prefrontal cortex to the nucleus accumbens and the ventral tegmental area, are not essential for the acquisition of schedule-induced drinking.

Animals↗

PubMed1986

A VIP/PHI-containing pathway links urinary bladder and sacral spinal cord.

Nerve fibres containing VIP and the co-produced PHI are found in the dorsal horn and autonomic centres of the sacral spinal cord and in pelvic organs. We have investigated the origin of these nerve fibres and a possible peptide-containing pathway linking pelvic viscera with the spinal cord of the cat and rat using neurochemical and neurosurgical procedures, retrograde tracing and immunocytochemistry. Cell bodies were located in the dorsal root ganglia (after colchicine injection), pelvic ganglia and bladder wall. Capsaicin treatment induced a loss of VIP/PHI from the dorsal horn. Retrograde tracing from the bladder revealed True Blue labelled cells in the dorsal root ganglia (L6, S1), parasympathetic nuclei and pelvic ganglia. Labelled cells were sequentially immunostained for VIP/PHI which were numerous in pelvic ganglia and scattered and weak in dorsal root ganglia. Pelvic nerve section induced a decrease of VIP/PHI immunoreactivity from the spinal cord and no change or a minimal increase in immunoreactive nerve fibers of the bladder. Thus pelvic visceral afferents with cell bodies in the dorsal root ganglia are a significant source of VIP/PHI-containing fibres in the sacral dorsal horn.

Afferent Pathways↗

PubMed1986

Calcitonin gene-related peptide immunoreactivity in afferent neurons supplying the urinary tract: combined retrograde tracing and immunohistochemistry.

The innervation of rat and guinea pig urinary tract was examined using immunohistochemistry, radioimmunoassay and True Blue retrograde tracing techniques and was further assessed following both surgical and chemical denervation experiments. Substantial amounts of calcitonin gene-related peptide-like immunoreactivity (range 20-150 pmol/g) were detected in tissue extracts and localised to nerve fibres distributed throughout the urinary tract of both species, these being concentrated in the ureter and base of the bladder. In the guinea pig, the number and distribution pattern of calcitonin gene-related peptide-like immunoreactive nerves appeared to be identical to that of substance P-containing nerves, whereas in the rat the former predominated. Seven days after injection of the fluorescent dye True Blue into tissues of the urinary tract, retrogradely labelled cells were found in the dorsal root ganglia. These cells had a segmental distribution pattern which was specific for each of the injection sites. Thus, after injection of True Blue into the left kidney hilum a single group of labelled cells were found in the ipsilateral T10-L2 dorsal root ganglia. In contrast, injection into the left ureter produced labelled cells in two separate groups of ipsilateral ganglia (T11-L3 and L6-S1). Injection into the wall of the bladder and upper urethra resulted in bilateral labelling, with most labelled cells occurring in L6 and S1 ganglia. Approximately 90% of labelled cells in T10-L3 dorsal root ganglia displayed calcitonin gene-related peptide-like immunoreactivity, but only 60% of retrogradely labelled bladder neurons in L6-S1 ganglia were immunoreactive for this peptide. Adult guinea pigs and neonatal rats injected systemically with capsaicin subsequently exhibited a marked reduction both in the amount of calcitonin gene-related peptide immunostaining and the concentration of immunoreactive material in the urinary tract, dorsal root ganglia and spinal cord. In rats treated neonatally with capsaicin, there was a significant reduction in the number of retrogradely labelled cells and a hypertrophy of the bladder. Sectioning of the pelvic and hypogastric nerves in the rat also resulted in a depletion of calcitonin gene-related peptide-like immunoreactive nerves in the bladder, whereas chemical sympathectomy appeared to have no effect. The results indicate that calcitonin gene-related peptide immunoreactivity occurs in a major proportion of afferent neurons supplying the urinary tract of the rat and guinea pig.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1985

Presence of neuromedin B-like immunoreactivity in the brain and gut of rat and guinea-pig.

A recently developed specific radioimmunoassay for neuromedin B, originally isolated from porcine spinal cord, was used to investigate its distribution in rat and guinea-pig brain and gut. In both species, neuromedin B-like immunoreactivity was present in several regions of brain, and high concentrations occurred in the pituitary. The immunoreactivity was widely distributed throughout the entire length of gastrointestinal tract and pancreas, and relatively high concentrations were found in the oesophagus and rectum. Immunocytochemistry localised neuromedin B-like immunoreactivity to nerve fibers in the rat brain and gut. Immunoreactive fibres were visualized in the medial thalamus and were found very frequently in the circular muscle of the gut. Gel permeation chromatography of pituitary and intestinal extracts from both species revealed presence of two peaks of neuromedin B-like immunoreactivity, the later of which co-eluted with the synthetic porcine neuromedin B standard. Reverse phase high pressure liquid chromatography showed that material corresponding to the later peak was eluted in the exact position of synthetic porcine neuromedin B, whereas the larger molecular size material from the earlier peak was more hydrophobic in nature.

Amino Acid Sequence↗

PubMed1985

Distribution of galanin immunoreactivity in the central nervous system and the responses of galanin-containing neuronal pathways to injury.

Radioimmunoassay and immunocytochemistry were used to study the distribution of galanin, a novel 29 amino acid porcine intestinal peptide, in the central nervous system of the rat and pig. The pattern of distribution was similar in the two species, with the highest concentrations of galanin-like immunoreactivity found in the neurohypophysis, hypothalamus and sacral spinal cord. Immunocytochemical studies of these regions localized galanin-like immunoreactivity to cell bodies in the paraventricular and supraoptic nuclei of the hypothalamus, to fibres in the pars nervosa and to numerous cell bodies and fibres in the dorsal horn of the spinal cord. On both gel and high pressure liquid chromatography, galanin-like immunoreactivity in rat and pig nervous tissue eluted as a single peak in a position similar to purified procine intestinal galanin standard. Surgical and pharmacological manipulations in the rat suggest the presence of galanin in afferent fibres. An increase of galanin-like immunoreactivity was observed in the sacral spinal cord of the rat following thoracic spinal cord transection. Thus galanin-like immunoreactivity in the brain is mainly localized in the hypothalamopituitary region. The decrease of galanin-like immunoreactivity in the dorsal horn of the spinal cord, following dorsal rhizotomy and pre-treatment of rats with capsaicin, indicates that many of the fibres, which are of small diameter, may well be derived from spinal sensory neurones.

Animals↗

PubMed1985

Distribution and localization of neuromedin B-like immunoreactivity in pig, cat and rat spinal cord.

The distribution and localization of neuromedin B, a novel bombesin-like decapeptide isolated from porcine spinal cord, was investigated by newly established radioimmunoassay and immunocytochemistry in the pig, cat and rat spinal cord. Neuromedin B-like immunoreactivity was found to be concentrated particularly in the dorsal part of lumbosacral segments in all species studied and the highest concentration of immunoreactivity was 25.7 +/- 3.4 pmol/g wet wt in the dorsal part of sacral region of pig spinal cord. The nature of the immunoreactivity was studied by gel permeation and high pressure liquid chromatography. Chromatography of spinal cord extracts from three species revealed two major peaks of neuromedin B-like immunoreactivity and the prevalent molecular from co-eluted with synthetic porcine neuromedin B. Immunocytochemistry localized neuromedin B immunoreactivity to fibres and terminals throughout the entire length of the spinal cord of pig, cat and rat. Fibres were most abundant in laminae I and II of the dorsal horn, the area around the central canal (lamina X) and intermediolateral cell columns of thoracic and sacral segments. In lumbosacral segments neuromedin B-immunoreactive fibres were slightly more numerous, in both dorsal and ventral spinal cord, than in cervical and thoracic regions.

Animals↗

PubMed1984

Neurogenic extravasation and substance P levels are low in muscle as compared to skin the rat hindlimb.

Activation of cutaneous chemosensitive afferents results in the release of substances which increase the permeability of the microcirculation, producing inflammation. That this inflammation is neurogenic is readily demonstrated by antidromic electrical stimulation of afferent fibres. In the present study we have used the technique of dye extravasation to compare both qualitatively and quantitatively neurogenic extravasation skin and skeletal muscle. Plasma extravasation has been found to occur in skeletal muscle after stimulation but only at less than 10% of the levels seen in skin. We have also found that the levels of the C-fibre markers substance P and fluoride-resistant acid phosphatase are greatly reduced in muscle compared with skin nerves. These results show that there are substantial differences in the population of C-fibres supplying muscle compared with those supplying skin.

Animals↗

PubMed1984

Neuropeptide Y in human spinal cord.

The distribution of a newly described peptide, neuropeptide Y (NPY) within the human spinal cord has been determined using radioimmunoassay and immunocytochemistry. Higher concentrations were found in the lumbar (49.9 +/- 6.8 pmol/g) and sacral (47.0 +/- 10.6 pmol/g) regions than in the cervical (27.6 +/- 2.7 pmol/g) and thoracic spinal cord (33.8 +/- 5.3 pmol/g). Immunocytochemistry revealed numerous nerve fibers containing NPY in the spinal cord; these were particularly concentrated in the substantia gelatinosa of the dorsal horn. In the ventral spinal cord NPY-containing nerves were sparse becoming more abundant in lumbosacral segments.

Adult↗

PubMed1984

The distribution and origin of a novel brain peptide, neuropeptide Y, in the spinal cord of several mammals.

The distribution of neuropeptide Y [NPY]-immunoreactive material was examined in the spinal cord and dorsal root ganglia of rat, guinea-pig, cat, marmoset, and horse. Considerable concentrations of NPY and similar distribution patterns of immunoreactive nerve fibres were found in the spinal cord of all species investigated. The dorsal root ganglia of the cat and the horse contained numerous immunoreactive nerve fibres, but in these species, as in the other three studied [rat, guinea-pig, marmoset], no positively stained cell bodies were found. Neuropeptide Y-immunoreactive nerves were observed at all levels of the spinal cord, being most concentrated in the dorsal horn. In the rat, guinea-pig, and marmoset, there was a marked increase of NPY-immunoreactive fibres in the lumbosacral regions of the spinal cord, and this was reflected by a considerable increase of extractable NPY. Estimations of NPY-immunoreactive material in the various regions of the rat spinal cord were as follows: cervical, 13.8 +/- 1.0; thoracic, 21.1 +/- 2.5; lumbar, 16.3 +/- 2.9; sacral, 92.4 +/- 8.5 pmol/gm wet weight of tissue +/- SEM. In the ventral portion of the guinea-pig spinal cord they were as follows: cervical, 7.1 +/- 1.2; thoracic, 8.2 +/- 3.6; lumbar, 22.6 +/- 7.0; sacral, 36.7 +/- 9.5 pmol/gm wet weight of tissue +/- SEM. Analysis of spinal cord extracts by reverse phase high performance liquid chromatography [HPLC] demonstrated that NPY-immunoreactive material elutes in the position of pure NPY standard. No changes in the concentration and distribution of the NPY-like material in the rat spinal cord were observed following a variety of surgical and pharmacological manipulations, including cervical rhizotomy, sciatic nerve section and ligation, and local application of capsaicin [50 mM] to one sciatic nerve. It is therefore suggested that most of the NPY-immunoreactive material in the spinal cord is derived either from intrinsic nerve cell bodies or from supraspinal tracts.

Animals↗

PubMed1984

A novel substance P pathway linking the dorsal and ventral horn in the upper lumbar segments of the rat spinal cord.

We report here the presence of a novel substance P pathway existing at a segmental level in the upper lumbar region (L1/L2) of the rat spinal cord. Substance P-containing fibres were seen directly linking a number of discrete areas of the rat spinal cord, including dorsal and ventral regions. These fibers were found closely associated with a specific group of motoneurones, the mediolateral motor nucleus in the ventral horn. This motoneurone group appeared as a 'focusing' nucleus around which substance P-containing tracts appeared to congregate. An intrinsic spinal cord origin of substance P-containing neurones in these interconnecting pathways is suggested as deafferentation achieved either by section of appropriate dorsal roots, or pharmacologically by neonatal treatment with capsaicin, had no effect on the appearance of the nucleus in the ventral spinal cord or of the associated substance P-containing tracts. Likewise, mid-thoracic lesions of the spinal cord (to determine supraspinal contributions) including hemisection, dorsolateral funiculus lesions and lesions of the region around the central canal, induced no change. The significance of these interconnecting substance P-immunoreactive fibre tracts is not known. However, the intimate association of substance P-containing fibres with a specific group of motoneurons indicates that they may modulate motor function.

Afferent Pathways↗

PubMed1984

PHI-like immunoreactivity co-locates with the VIP-containing system in human lumbosacral spinal cord.

Using a specific radioimmunoassay and immunocytochemistry, the quantitative regional distribution and localization of PHI-like immunoreactivity was studied in normal postmortem human spinal cord. The levels of PHI-like immunoreactivity were low in the cervical and thoracic region whereas the lumbar and especially sacral regions showed higher levels, with dorsal sacral concentrations exceeding ventral concentrations. Chromatographic analysis by high pressure liquid chromatography revealed that the PHI-like immunoreactivity in human spinal cord elutes slightly earlier than pure porcine PHI, and may correspond to PHM-27, a PHI-27-like peptide found in human preprovasoactive intestinal polypeptide. Immunocytochemical studies show a distinctive distribution of PHI-like immunoreactive fibres and terminals at the lumbosacral segments. The distribution of PHI-like immunoreactivity is thus similar to that of VIP, and unlike a number of other neuropeptides; with VIP, it may mark a system which has a role in the spinal control of urogenital function in man.

Aged↗