Levels Of Substance P-like Immunoreactivity Research Articles

Prenatal Exposure to Nicotine Affects Substance P and Preprotachykinin-A mRNA Levels in Newborn Rat

Prenatal nicotine exposure influences neuronal development including effects on several neurotransmitter systems. It also attenuates the ventilatory response to hypoxia, known to require a functional substance P-ergic system. Previous studies have shown that nicotine increases the risk for sudden infant death syndrome (SIDS) by 4-fold, and that SIDS-victims have elevated brainstem levels of substance P. We, therefore, studied the effect of prenatal nicotine exposure on the levels of substance P-like immunoreactivity by RIA in the brain in newborn rat pups. The expression of the substance P precursor preprotachykinin A mRNA was also determined by real-time reverse transcriptase-polymerase chain reaction in carotid body, in petrosal/jugular and trigeminal ganglia, in cervical and lumbar dorsal root ganglia, and in the brainstem. We found that prenatal nicotine exposure increased levels of substance P-like immunoreactivity in the brainstem without changing levels in other parts of the brain or in the adrenals. Furthermore, mRNA levels were increased in the carotid bodies and in the petrosal ganglia, in contrast to the decreased levels in the cervical dorsal root ganglia. We conclude that nicotine causes alterations in the substance P-ergic system in the brainstem, possibly linked to the increased risk for SIDS after prenatal nicotine exposure.

Substance P in human tears.

To determine the levels and biochemical characteristics of substance P-like immunoreactivity (SPLI) in human tears and ascertain whether substance P (SP) concentrations in tears reflect the condition of the ocular surface. Unstimulated tears were collected with a micropipette. Tear samples were partially purified using C-18 cartridges. Levels of SPLI in purified samples were measured using an enzyme immunoassay (EIA). For biochemical characterization of SPLI, tear extracts were fractionated using high-performance liquid chromatography (HPLC); each fraction was then subjected to EIA. To determine the catabolism of SP in tears, synthetic SP was incubated in medium containing pooled tears and then analyzed using HPLC. The concentration of SPLI in normal human tears was 306.0 +/- 96.5 pg/mL (mean +/- SD, range 148-555 pg/mL). Levels of SPLI did not vary significantly by age or gender. Concentrations of SPLI in tears from eyes with unilateral corneal hypesthesia were lower than those in tears from contralateral healthy eyes. Diclofenac sodium eye drops reduced concentrations of prostaglandin E2 and SPLI in tears. Analysis using HPLC indicated that five different substances contributed to SPLI in tears and that SP was broken down into several fragments, including SP(8-11), by enzymes present in tears. Substance P is a normal component of human tears. Levels of SPLI in tears might reflect the denervated status of the ocular surface. Substance P is catabolized by degradative enzymes in tears to maintain the ocular surface by exerting the trophic effects of SP while avoiding undesirable effects.

Spinal substance P release in vivo during the induction of long-term potentiation in dorsal horn neurons

Long-term potentiation (LTP) in wide dynamic range (WDR) neurons in the dorsal horn has been suggested to contribute to central sensitization and the development of chronic pain. Indirect experimental evidence indicates an involvement of substance P (SP), in this respect. The aim of the present study was to monitor the extracellular level of substance P-like immunoreactivity (SP-LI) in the dorsal horn of the rat during and after induction of LTP in WDR neurons in vivo. Electrophysiological recordings of single (WDR) neurons were performed in parallel with microdialysis in the dorsal horn under urethane-anaesthesia. The amount of SP-LI in the microdialysate was determined by radioimmunoassay. As previously shown, high frequency conditioning stimulation of the sciatic nerve induced an increased firing response of WDR neurons. An increased response to C-fibre stimulation, but not A-fibre stimulation, could be determined. A significant increase of the extracellular level of SP-LI in the dorsal horn was detected during, but not after, induction of LTP. These data suggest that SP may be involved in the induction of LTP by high frequency stimulation. However, the maintenance of spinal LTP following high frequency peripheral nerve stimulation does not seem to depend on an increased release of SP.

Elevated substance-P-like immunoreactivity levels in spinal dialysates during the formalin test in normal and diabetic rats

Pharmacologic studies implicate the involvement of substance P in spinal nociceptive processing during the formalin test. However, no direct measurement of the temporal changes in substance P levels within the spinal cord of conscious animals has been reported. Further, dissociation between substance P levels and formalin-evoked nocifensive behavior may exist in diabetic rats, as exaggerated hyperalgesic behavior coexists with reduced peripheral nerve substance P levels. The present study was performed to directly measure the appearance of substance-P-like immunoreactivity (SP-LI) in spinal CSF of conscious, unrestrained rats using microdialysis techniques following injection of formalin into the hindpaw. The effect of diabetes upon formalin-evoked SP-LI levels in spinal CSF dialysates was also determined. In control rats, SP-LI increased in spinal dialysates following formalin injection and levels were maximal 20–30 min after injection, rising to 325% of basal values ( p<0.02). Diabetic rats exhibited reduced ( p<0.05) SP-LI in their spinal roots, while basal levels in spinal CSF were not different from controls. Formalin-evoked nocifensive behavior was increased in diabetic rats but SP-LI levels in spinal CSF dialysates after paw formalin injection were significantly ( p<0.05) attenuated, reaching a maximum of only 161% of basal levels. This was accompanied by attenuated swelling at the formalin injection site and increased thermal response latencies. While increased SP-LI in spinal CSF coincides with phase 2 behavior in the formalin test and may contribute to spinal nociceptive processing during this period, exaggerated spinal substance P release is unlikely to underlie the increased nocifensive behavior seen in diabetic rats.

No release of histamine and substance P in capsaicin‐induced neurogenic inflammation in intact human skin in vivo: a microdialysis study

Studies in rodents' skin have indicated substance P to be the main inflammatory mediator involved in neurogenic inflammation, acting partly by release of histamine from skin mast cells. The mediators released in neurogenic inflammation in human skin remain to be determined. To determine the effects of intradermally injected and topically applied capsaicin on the release of histamine and substance P and skin responses in intact human skin in vivo. Extracellular skin levels of histamine and substance P were measured by microdialysis technique and assayed by enzyme and radio immunoassays. Two kinds of dialysis fibres (210 microm, 2 kDa, and 500 microm, 20 kDa) were inserted intradermally into forearm skin for studies of histamine release to topically administered capsaicin and intradermally injected capsaicin and substance P. Baseline histamine skin levels were 8.0 +/- 0.7 nM. Intradermally injected capsaicin (0.3-30 microM, 7.5-750 pmol) caused significantly and dose-related flare and pain reactions, but no significant histamine release or weals. Intradermally injected substance P (1 and 3 microM, 25 and 75 pmol) released significant amounts of histamine (peak levels being 90 and 475 nM), evoked weal-and-flare reactions, but did not cause pain. Capsaicin 2% ointment, applied on the skin for 2.5 h, increased skin blood flow by 300-400% as measured by laser Doppler flowmetry, elicited a longstanding burning sensation, but did not release histamine. Substance P-like immunoreactivity (SP-LI) was below the 1.8 pM detection limit following insertion of 20 kDa dialysis fibre and after intradermal injection of capsaicin 3 microM. Intradermal injection of injection of 1 microM of substance P increased SP-LI levels to values greater than 4500 pM, confirming the ability of the dialysis fibre to recover this peptide. Capsaicin-induced neurogenic activation does not involve the release of histamine from mast cells or detectable amounts of substance P release from sensory nerves in normal human skin in vivo.

Elevated Cerebrospinal Fluid Substance P-like Immunoreactivity in Patients with Painful Osteoarthritis, but not in Patients with Rhizopatic Pain from a Herniated Lumbar Disc

Cerebrospinal fluid (CSF) levels of substance P like immunoreactivity (SPLI) were determined in 11 patients with painful osteoarthritis in hip or knee, 9 patients with rhizopatic pain from a herniated lumbar disc, and in 9 healthy volunteers without pain. The patients with osteoarthritis had increased levels of SPLI in CSF (p< 0.001) compared to the controls. A positive correlation was also seen between the CSF SPLI and the degree of pain. At a second lumbar puncture 5 months after operation, SPLI had decreased, but was still significantly higher than in the controls.No difference in CSF SPLI was seen in the patients with herniated lumbar disc compared to the controls, neither before treatment, nor at follow up CSF postoperatively. The results suggest that nociceptive joint pain is consistent with increased SPLI in CSF. Differences in SPLI in CSF may be useful to differentiate pain from various origin, and may also increase our understanding of different pain mechanisms.

Endogenous mono-ADP-ribosylation in retina and peripheral nervous system. Effects of diabetes.

The extranuclear endogenous mono-ADP-ribosylation of proteins was monitored in cellular preparations of retina, superior cervical ganglion, dorsal root ganglia and peripheral nerve. At least 6 protein fractions are ADP-ribosylated in the crude extract fraction from retina control preparations, while in diabetic rats the number of retina labeled proteins and the extent of labeling are highly reduced. In the superior cervical ganglion labeling was present in 10 proteins, in diabetics it was greatly decreased. Treatment of diabetic rats with silybin, a flavonoid mono-ADP-ribosyltransferase inhibitor, did not affect hyperglycemia, but prevented the alteration of extent of protein ADP-ribosylation. These data suggest that proteins of retina and peripheral ganglia are excessively ADP-ribosylated in vivo. The effects of silybin treatment on excessive mono-ADP-ribosylation of proteins was associated with the prevention of reduction of substance P-like immunoreactivity levels, that is typical of diabetic neuropathy. In the membrane fraction of sciatic nerve Schwann cells, at least 9 proteins were ADP-ribosylated, diabetes caused a marked increase of labeling. A comparable increase involving the same proteins is triggered by chronic nerve injury and by corticosteroid treatment. Silybin treatment of diabetic rats prevented such an increase. We propose that the inhibition of excessive protein mono-ADP-ribosylation by silybin prevented the onset of diabetic neuropathy. While the effects on Schwann cells is likely indirect and secondary to the improvement of diabetic axonopathy.

The effects of pregnancy and parturition on the levels of substance P-like immunoreactivity in different areas of the hypothalamus

1. 1. The concentrations of substance P-like immunoreactivity (SPLI) have been measured in the rostral and caudal areas of the hypothalamus of male rats and of virgin, pregnant and puerperal female rats. 2. 2. The rostral:caudal ratio of SPLI is similar in males and virgin females, but diminishes in pregnancy and decreases further during the puerperium. In the pre-optic area, the SPLI concentration fell significantly during parturition, from 241.8 to 177.2 pmols/g wet weight ( P < 0.05), and in the medio-basal hypothalamus, the concentration rose during pregnancy and parturition, from 87.4 to 145.5 pmols/g wet weight ( P < 0.001). 3. 3. The results are discussed in relation to the endocrine and nociceptive aspects of pregnancy and parturition.

Clomipramine and clonazepam increase cholecystokinin levels in rat ventral tegmental area and limbic regions

Recent reports suggest that a cholecystokinin (CCK)-related dysfunction may be a target by which drugs can modulate anxiety and panic disorders. In the present study, effects of subchronic (14 days) treatment with the monoamine uptake inhibitors nortriptyline (30 μmol/kg per day), amitriptyline (29 μmol/kg per day), clomipramine (32 μmol/kg per day) and alaproclate (39 μmol/kg per day), as well as with the benzodiazepine clonazepam (0.25 μmol/kg per day), on rat brain levels of CCK- and substance P-like immunoreactivity, were compared. The drugs were administered by continuous s.c. infusion using implanted osmotic pumps. The plasma concentrations of the monoamine uptake inhibitors were similar after 1 and 2 weeks of treatment, indicating that steady-state plasma levels had been reached during the first week. Treatment with clomipramine or clonazepam increased the CCK-like immunoreactivity level in the ventral tegmental area ( by 64.4 ± 28.8% and 105.1 ± 28.8% , respectively) and in the cingulate cortex ( by 30.3 ± 10.1% and 36.0 ± 11.8% , respectively) ( P < 0.05 or P < 0.01 ). Clomipramine also significantly increased the CCK-like immunoreactivity level in the periaqueductal grey by 85.1 ± 29.7%. Neither nortriptyline nor amitriptyline or alaproclate produced any significant alterations in the CCK- or substance P-like immunoreactivity levels in the areas examined. The present results may suggest that an altered utilization of CCK in limbic circuits could be of importance for the well documented clinical effect of clomipramine and clonazepam in panic disorders.

Prevaccination with diluted freund adjuvant prevents the development of chronic pain and transient release of cerebrospinal fluid substance P in adjuvant-induced arthritis in rats

Parallel time courses of preclinical and behavioural pain-related parameters and levels of substance P-like immunoreactivity in plasma (plasma-SPLI) and cerebrospinal fluid (CSF-SPLI) were studied in 2 groups of rats injected with an arthritogenic solution (concentrated Freund adjuvant) over a 9-week post-infection (PI) period; 1 group was pretreated with saline (control) and 1 pretreated with diluted Freund adjuvant (immunized). In control rats all symptoms of adjuvant-induced arthritis (AIA) developed while in immunized rats AIA symptoms were significantly reduced or did not appear. A significant increase in plasma-SPLI was obvious as early as the 2nd week PI and remained at this level in both groups of animals until the end of the 9-week PI observation period, but with a significantly higher increase in control versus immunized group at all stages. In contrast, CSF-SPLI transiently peaked only in the control group at 3 weeks PI whereas CSF-SPLI values did not differ from one week to another in both groups of rats. These results suggest that successive injections of diluted Freund adjuvant impairs the development of chronic inflammation and pain in AIA in rats, as well as the transient increase in SP release in CSF at 3 weeks PI, but not the long-lasting increased SP release in plasma. Since there is a clear dissociation between our biochemical and preclinical and behavioral data, this study does not provide evidence for the role of substance P as a possible biologic marker of chronic pain either in plasma or in CSF. This study questions the use of SP measurements as a biological marker of chronic pain.

Time course of variations in rabbit cerebrospinal fluid levels of calcitonin gene-related peptide- and substance P-like immunoreactivity in experimental subarachnoid hemorrhage.

Cerebral vasospasm after subarachnoid hemorrhage may result partially from the imbalance between vasodilator and vasoconstrictor factors. The vasodilator peptides substance P and calcitonin gene-related peptide contained in the trigeminovascular system are involved in the vasomotor phenomenon occurring after subarachnoid hemorrhage. The delayed arterial narrowing may reflect the time course of the release of these peptides. Therefore, we followed the time course of the changes in cerebrospinal fluid immunoreactivity of substance P and calcitonin gene-related peptide in a model of experimental subarachnoid hemorrhage. Cerebrospinal fluid samples were taken in the basal state and at 30 minutes, 24 hours, and 3 days after a single injection of 1 mL autologous arterial blood into the cisterna magna of rabbits using a percutaneous suboccipital route. Substance P-like and calcitonin gene-related peptide-like immunoreactivities were determined in centrifuged cerebrospinal fluid and plasma by use of enzyme immunoassay. Early (30 minutes) after induced subarachnoid hemorrhage, there was a large increase in cerebrospinal fluid substance P-like immunoreactivity (P < .01) and calcitonin gene-related peptide-like immunoreactivity (P < .01). Arterial and hemorrhagic cerebrospinal fluid levels of substance P-like immunoreactivity were different (P < .03), indicating that the increased cerebrospinal fluid level did not result only from the blood contamination. Twenty-four hours after induced subarachnoid hemorrhage, the immunoreactivities of substance P and calcitonin gene-related peptide remained significantly higher than the basal level (P < .01). At day 3, both immunoreactivities had decreased to a level nonsignificantly different from the basal level. The early high values of the cerebrospinal fluid immunoreactivities for substance P and calcitonin gene-related peptide, apart from the contamination by arterial blood, probably resulted from the depletion of neurotransmitter peptides from the trigeminovascular fibers.

Relative contribution of sympathetic and sensory nerves to thermal nociception and tissue trophism in rats

Neonatal injection of 6-hydroxydopamine (420 mg/kg s.c.) lowered thermal nociceptive threshold (hot plate and tail immersion tests) and increased levels of substance P-like immunoreactivity in the skin (paws, tail, area of vibrissae) of Wistar rats. Chemical ablation of primary afferents, induced in either neonatal or adult rats by systemic administration of capsaicin, increased thermal nociceptive threshold (hot plate), irrespective of 6-hydroxydopamine pretreatment, and reduced substance P-like immunoreactivity in the hind-paw skin of either control or sympathectomized rats. Capsaicin pretreatment of neonatal but not adult rats produced antinociceptive effect in the tail-immersion test and completely reversed the hyperalgesic effect of sympathectomy, without affecting levels of substance P-like immunoreactivity in the tail skin. These findings indicate that sympathetic nerves and different subsets of capsaicin-sensitive primary afferents are involved in the processing of thermal nociceptive input. Corneal and cutaneous lesions were induced by neonatal sensory denervation with capsaicin. Sympathectomy afforded protection against the development of corneal pathology, while it did not affect the occurrence of cutaneous lesions. It appears that a balance in the neuronal activity between sympathetic neurons and trigeminal sensory neurons is critical for maintaining the normal trophism of the cornea, and that sensory neuropeptides play a key role in the maintenance of normal trophism of the skin.

Substance p in cutaneous primary sensory neurons—a comparison of models of nerve injury that allow varying degrees of regeneration

We have Studied changes in Neuropeptide expression in four Different models of nerve injury in adult rats. The models involved the cutaneous sural and saphenous nerves, and were associated with different degrees of regrowth and peripheral target reinnervation. These were: simple crush of the nerve, complete cut and self-anastomosis; cut and ligation, and cut and anastomosis of the nerve to an isolated stump of peripheral nerve. Thus, in the first two models a partial or complete reinnervation of peripheral targets was possible, while in the third and fourth it was not. The last model allowed regenerating fibres to come into contact with Schwann cells in the distal stump. We measured substance P-like immunoreactivity in the manipulated nerves (by radioimmunoassay) and the number of manipulated afferents expressing the peptide in dorsal root ganglion cells (by combined immunohistochemistry and retrograde labelling), at time points up to 12 weeks after the nerve manipulations. The retrograde labelling also allowed estimates of cell death. Two weeks after the nerve injuries, when no cell death had occurred, the nerves subjected to a cut lesion (last three models) all showed very low levels of substance P-like immunoreactivity, both in the amounts in peripheral nerve, and in the number of manipulated cell staining positively ( P < 0.01). In contrast, the crush model showed no significant change in substance P levels in the nerve ( P ≫ 0.05), but a significant increase in the number of immunopositive cells ( P < 0.01). Twelve weeks after the nerve manipulations, a variable degree of cell death was seen. Only 9% of afferents in the crush model were lost ( P ≫ 0.05 compared with normal) but a 39 and 45% loss was seen in tie and resuture models, respectively, ( P < 0.05 for both, compared with normal), and a 63% loss in the stump model ( P < 0.01 compared to normal, and P < 0.05 compared to tie and resuture models). An analysis of cell size distributions indicated that cell death affected both large and small cells. At 12 weeks, the levels of substance P in the first two models (associated with peripheral reinnervation) had returned towards, but did not reach, normal ( P < 0.01), whilst the stump model showed no significant recovery and the tie model was intermediate. Proportionately more manipulated cells were found to express substance P immunoreactivity in the stump model than expected after allowing for cell death. The maintenance of substance P levels and lack of cell death in the crush model are unlikely to be explained by the regrowing sprouts coming into immediate contact with Schwann cells in the distal nerve. The results invite speculation that cut axons may allow the accumulation and entry of positively harmful factors, and the double lesion associated with the stump model may exaggerate their actions here.

CALCITONIN GENE-RELATED PEPTIDE II, SUBSTANCE P AND VASOACTIVE INTESTINAL PEPTIDE IN PLASMA AND SYNOVIAL FLUID FROM PATIENTS WITH INFLAMMATORY JOINT DISEASE

Immunoreactive plasma and synovial fluid concentrations of calcitonin gene-related peptide II (CGRP II), substance P and vasoactive intestinal peptide (VIP) were measured in patients with osteoarthritis, gout and rheumatoid arthritis. Significantly higher levels of CGRP II and substance P-like immunoreactivity levels in synovial fluid were found in gout as well as CGRP II, substance P and VIP-like immunoreactivities in rheumatoid arthritis when compared to those in osteoarthritis. Plasma CGRP II, substance P and VIP-like immunoreactivity levels showed no significant differences among patients in the three different groups of arthritis. Our results suggest that these neuropeptides released from peripheral nerve endings into the synovial cavity probably play a pathogenic role in human joint inflammation.

Short‐term restraint stress and s.c. saline injection alter the tissue levels of substance P and cholecystokinin in the peri‐aqueductal grey and limbic regions of rat brain

Rats were exposed to short-term restraint (held by the tail for 1 min), injected s.c. with saline or subjected to the combination of these treatments. Fifteen and 30 min after these treatments the means serum corticosterone level was significantly increased by more than four times, compared to rats taken directly from their home cages, indicating a stress response. In the peri-aqueductal grey, the level of substance P-like immunoreactivity was increased by 45% (P < 0.01) and 65% (P < 0.01) 30 and 60 min after the combined treatment, respectively. Significant increases of the level of substance P-like immunoreactivity in the peri-aqueductal grey were also found after restraint only and after a s.c. saline injection. Similar, but less marked, changes in the level of cholecystokinin-like immunoreactivity in the PAG were also seen. In the accumbens a significantly decreased level of substance P-like immunoreactivity was encountered at 15 and 30 min after treatment, while the levels of cholecystokinin- and neuropeptide Y-like immunoreactivity were not significantly changed. In other regions studied, no effects on peptide levels were seen. The changes in peptide levels had a time course similar to that of the increase in serum corticosterone. Also the successive removal of rats from a common cage was found to increase significantly the serum corticosterone and the substance P-like immunoreactivity in the peri-aqueductal grey in the animals that were taken late in sequence from the cage.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of an antiserum to the midportion of substance P: applications for biochemical and anatomical studies of substance P-related peptide species in CNS tissues.

This report describes the generation and biochemical characterization of a high-affinity antiserum that recognizes an epitope contained in the midportion sequence of substance P, i.e., substance P4-10. Designated A47, this reagent bound a variety of related peptide species containing the substance P4-10 sequence with apparent equipotency. A double radioimmunoassay procedure was developed that utilized A47, in combination with a traditional high-affinity COOH-terminally directed anti-substance P serum, to provide quantification of mature and immature forms of substance P in CNS tissues. Across most rat CNS areas, levels of substance P-like immunoreactivity were consistently 15% higher when monitored by analyses using A47 versus anti-substance P serum. In the dorsal root ganglia, an apparent enhancement in levels of substance P-like immunoreactivity of approximately 40%, when quantified by analyses using A47 versus anti-substance P serum, was observed; this most likely reflected the presence of an active biosynthetic pool of intermediate processing forms of substance P in this tissue. Coordinated HPLC/radioimmunoassay analyses of extracted dorsal root ganglia tissues demonstrated multiple peaks of immunoreactivity corresponding to mature substance P and to several of its precursor forms found in the normal biosynthetic pathway. Of the total recovered HPLC-fractionated immunoreactivities, that corresponding to the putative immediate precursor to substance P, i.e., substance P-glycine, was the predominant peak. In an additional series of HPLC/radioimmunoassay analyses, selective decreases in immunoreactive peaks corresponding to precursor forms of substance P were observed in dorsal root ganglia tissues from rats treated with the neurotoxic agent capsaicin. These results indicated decreased turnover of substance P as a consequence of drug treatment. Finally, initial immunohistochemical analyses employing affinity-purified A47 produced an unusual pattern of labeling characterized by well defined punctate terminal elements within the superficial aspects of the dorsal horn of the spinal cord.

Ventricular fluid neuropeptides in Parkinson's disease. II. Levels of substance P-like immunoreactivity

Substance P-like immunoreactivity (SPLI) was determined in cerebroventricular fluid of patients with extrapyramidal motor diseases. Patients with Parkinson's disease (PD) showed a SPLI concentration decreased by 30% compared with patients without extrapyramidal disease. No differences were apparent for patients with dystonia. Fluid obtained from the foramen Monro showed higher SPLI concentrations than fluid from a lateral ventricle, indicating that hypothalamic sources are important for ventricular substance P. Lateral ventricular SPLI was particularly low in parkinsonian patients which raises the possibility of a decreased SPergic activity in basal ganglia occurring in PD.

Cerebrospinal fluid levels of immunoreactive substance P and somatostatin in patients with multiple sclerosis and inflammatory CNS disease

Cerebrospinal fluid (CSF) levels of substance-P like immunoreactivity (SPLI) and somatostatin-like immunoreactivity (SLI) were measured in 43 patients with multiple sclerosis (MS), differentiated according to course and activity of the disease, in 23 patients with inflammatory disease of known bacterial or viral etiology and in 16 control patients using specific radioimmunoassay. SPLI and SLI levels were not significantly different from controls in MS patients whereas SLI was significantly increased in patients with infectious disease of central nervous system and/or subarachnoidal space. It is assumed that CSF SPLI and SLI cannot serve as a diagnostic or prognostic indicator of disease state in multiple sclerosis. Analysis of immunoreactivity by reverse phase HPLC-RIA revealed marked molecular heterogeneity of both neuropeptides.

Substance P levels in peripheral nerve, skin, atrial myocardium and gastrointestinal tract of rats with long-term diabetes mellitus: Effects of aldose reductase inhibition

This study measured the content of substance P-like immunoreactivity (SPLI) in peripheral nervous tissue (lumbar dorsal root ganglia, sciatic nerve), skin (snout, foot), gastrointestinal tract (stomach, terminal ileum) and in the atria of the heart. Animals studied were long-term (11 months) streptozotocin-diabetic rats compared with age-matched control rats. All diabetic rats were given a very long acting insulin preparation twice weekly to reduce morbidity. Half of the diabetic rats were given the aldose reductase inhibitor, sorbinil (mean dose 30 mg/kg/day body weight by dietary admixture) over the entire protocol. Diabetic rats (given insulin only) showed marked accumulation of sorbitol and fructose together with myo-inositol depletion in their sciatic nerves. The sciatic nerves of the sorbinil-treated diabetic rats contained amounts of sorbitol, fructose and myo-inositol which were similar to those of non-diabetic rats, in spite of large amounts of nerve glucose in the sorbinil-treated animals. Thus, the inhibition of aldose reductase was successful. The L 4 and L 5 dorsal root ganglia of the diabetic rats showed reduced SPLI (63% and 72% respectively of control ganglia; P < 0.05). There was also numerical reduction in sciatic nerve SPLI (84% of control nerve). There were no effects of sorbinil treatment on the reduced SPLI levels in ganglia or sciatic nerve. In the gastrointestinal tract the levels of SPLI were reduced in diabetic rats even when data were adjusted to take account of tissue hypertrophy (diabetic SPLI/whole stomach was 60% controls, P < 0.01 and SPLI/cm ileum was 78%, though the latter did not attain statistical significance). In skin SPLI/unit area was raised in the diabetic rats to 145% of controls for foot skin and 151% for snout skin. Changes in SPLI content of gastrointestinal tract were unaffected by sorbinil treatment; in the skin the elevations were enhanced to 188% and 270% of respective control values for foot and snout skin. The SPLI content of the atria was unaffected by diabetes or sorbinil. These data are not consistent with a generalised impairment of delivery of substance P by axonal transport in experimental diabetes; special factors appear to influence the levels in neurones innervating different tissues. Exaggerated flux through the polyol pathway appears to be uninvolved.

Immunoreactive Substance P and Somatostatin in the Cerebrospinal Fluid of Senile Parkinsonian Patients

The concentration of substance-P-like immunoreactivity (SPLI) and somatostatin-like immunoreactivity (SLI) in the lumbar spinal fluid of senile parkinsonian patients (mean age 77.6 +/- 6.7 years) and senile control patients (mean age 83.5 +/- 5.6 years) were determined by specific radioimmunoassays. Mean SPLI and SLI levels in the control group were 8.1 +/- 2.0 (SD) and 32.5 +/- 12.0 fmol/ml, respectively. The mean SPLI levels were not significantly different in the groups. The mean SLI level was significantly lower in the group of patients with Parkinson's disease (19.8 +/- 9.0 fmol/ml). A comparison with results in patients with senile dementia of Alzheimer type (SDAT) shows that, in addition to clinical and pathological correlations, Parkinson's disease of late onset may share a deficit in somatostatinergic neuromodulation with SDAT.