Substance P-like Immunoreactivity Content Research Articles

Responses of limbic and extrapyramidal substance P systems to nicotine treatment.

Neuropeptides are linked to the psychopathology of stimulants of abuse, principally through dopamine mechanisms. Substance P (SP) is one of these neuropeptides and is associated with both limbic and extrapyramidal dopaminergic pathways and likely contributes to the pharmacology of these stimulants. The effects of nicotine on these dopamine systems have also been extensively studied; however, its effects on the associated SP pathways have received little attention. In the present study, we elucidated the effects of nicotine treatment on limbic and extrapyramidal SP systems by measuring changes in associated SP tissue concentrations. Male Sprague-Dawley rats received (+/-)nicotine 4.0 mg/kg/day (0.8 mg/kg, intraperitoneally; five injections at 2-h intervals) in the presence or absence of selective dopamine D1 and D2 receptor antagonists or a nonselective nicotinic acetylcholine receptor antagonist. The nicotine treatment significantly but temporarily decreased substance P-like immunoreactivity (SPLI) content in the ventral tegmental area (VTA) and substantia nigra 12-18 h after drug exposure. The nicotine-mediated changes in SPLI were selectively blocked by pretreatment with mecamylamine as well as a dopamine D1, D2, or both receptor antagonists. Other brain areas that also selectively demonstrated nicotine-related declines in SPLI content included prefrontal cortex, the nucleus accumbens shell, and the very posterior caudate. These findings indicate that some limbic and basal ganglia SP systems are significantly affected by exposure to nicotine through processes mediated by nicotinic and dopaminergic receptors, suggesting a role for SP pathways in nicotine's limbic and extrapyramidal effects.

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.

Responses of the extrapyramidal and limbic substance P systems to ibogaine and cocaine treatments

Ibogaine is an indolamine found in the West Africa shrub, Tabernanthe iboga, and has been proposed for the treatment of addiction to central nervous system (CNS) stimulants such as cocaine and amphetamine. The mechanism of ibogaine action and its suitability as a treatment for drug addiction still remains unclear. Since previous studies demonstrated differential effects of stimulants of abuse (amphetamines) on neuropeptide systems such as substance P, we examined the impact of ibogaine and cocaine on extrapyramidal (striatum and substantia nigra) and limbic (nucleus accumbens and frontal cortex) substance P-like immunoreactivity. Ibogaine and cocaine treatments altered substance P systems by increasing striatal and nigral substance P-like immunoreactivity concentration 12 h after the last drug treatment. However, substance P-like immunoreactivity content was not significantly increased in nucleus accumbens after treatment with either drug. The ibogaine- and cocaine-induced increases in substance P-like immunoreactivity in striatum and substantia nigra were blocked by coadministration of selective dopamine D 1 receptor antagonist (SCH 23390; R(+)-7-Chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride) or dopamine D 2 receptor antagonist (eticlopride; S(−)-3-Chloro-5-ethyl- N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxy-benzamide hydrochloride). Most of the responses by substance P systems to ibogaine administration resembled those caused by cocaine, except in cortical tissue where multiple administration of cocaine, but not ibogaine increased substance P-like immunoreactivity. These data suggest that substance P systems may contribute to the effects of ibogaine and cocaine treatment.

Plasma and saliva substance P levels: The effects of acute pain in pregnant and non-pregnant women

Substance P like immunoreactivity (SPLI) and total protein (TP) concentrations in plasma and saliva were measured in 80 healthy female patients divided into the following four groups: women in group 1 were not pregnant and they were awaiting tubal ligation; women in group 2 were not pregnant but they experienced acute postoperative pain following hysterectomy; women in group 3 were pregnant and were awaiting elective cesarean section; and women in group 4 were in active labor and experienced acute labor pain. Pain intensity was assessed using verbal Likert pain scores. The absolute measured concentration of SPLI (SPLI abs) was divided by the TP concentration to obtain corrected SPLI (SPLI corr) concentration. Results were expressed mean±1 SE and analyzed using analysis of variance with 95% confidence ( P<0.05). SPLI corr concentrations were 1.8±0.1, 1.8±0.2, 1.1±0.1, 1.1±0.1 pg/mg protein in groups 1, 2, 3 and 4, respectively. Patients in both pregnant groups had significantly lower plasma SPLI corr concentrations compared to the non-pregnant groups. However, the presence of acute postoperative pain or labor pain did not significantly alter plasma SPLI corr concentrations. Saliva SPLI concentrations were not significantly different among the four groups.

Effects of Repeated Sensory Stimulation (Electro‐acupuncture) and Physical Exercise (Running) on Open‐field Behaviour and Concentrations of Neuropeptides in the Hippocampus in WKY and SHR rats

The effects of repeated sensory stimulation (electro-acupuncture) and physical exercise (running) on open-field behaviour and on hippocampal concentrations of neuropeptide Y, neurokinin A, substance P, galanin and vasoactive intestinal peptide (VIP)-like immunoreactivities were studied in WKY (wistar-Kyoto) and SHR (spontaneously hypertensive) rats. Significantly higher concentrations of substance P-like immunoreactivity, neurokinin A-like immunoreactivity and neuropeptide Y-like immunoreactivity were found in the hippocampus immediately after 3 weeks of treatment (electro-acupuncture and running), but not 1 week after the last (tenth) changes in neuropeptide concentrations were similar in the two rat strains. Open-field behaviour was significantly reduced during the treatment period in both strains. There were significant negative correlations between behaviour and neuropeptide concentrations in SHR rats, suggesting interdependency with sympathetic activity. It is proposed that the effects of electro-acupuncture and physical exercise in rats are related to increases in neuropeptide Y, neurokinin A and substance P in the hippocampus.

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.

The effects of pregnancy and parturition on the substance P content of the rat uterus: uterine growth is accompanied by hypertrophy of its afferent innervation

The afferent innervation of the uterus might be expected to grow during pregnancy as the size of the uterus increases. Substance P-like immunoreactivity (SPLI) has been measured as a means of monitoring the changes in the afferent innervation of the urogenital tract of rats during pregnancy and following parturition. The great growth of uterine tissue during pregnancy causes an overall decrease in SPLI concentrations during pregnancy, but it has been found that the amount of SPLI present per uterine horn increases nearly 3-fold by the end of pregnancy. This increase is greater in uterine horns that contain more fetuses, suggesting that the SPLI innervation expands to a greater extent in uterine horns that undergo greater degrees of hypertrophy. There is a significant correlation between SPLI content and the number or total weight of fetuses throughout the latter two-thirds of pregnancy. There is a fall in SPLI content of uterine horns following parturition, but not to a statistically significant degree, and this may be related to the release of the peptide during parturition.

Diabetic neuropathy in the rat: 1. Alcar augments the reduced levels and axoplasmic transport of substance P

This study examined the sciatic nerve axonal transport of substance P-like immunoreactivity (SPLI) and its basal content in stomach, sciatic nerve and lumbar spinal cord of 8- and 12-week alloxan-diabetic rats, respectively. One group of diabetic rats received acetyl-l-carnitine (ALCAR) throughout the experimental period. Alloxan treatment caused hyperglycemia and reduced boy growth. Axonal transport of SPLI was studied by measurement of 24-hour accumulation at a ligature on the sciatic nerve. There was a marked reduction (from 50% to 100% according to the nerve segment examined) of anterograde and retrograde accumulation of SPLI in the constricted nerve of 8-week diabetic rats. In the sciatic nerve of ALCAR-treated diabetic rats, the accumulation of SPLI was comparable to control values. In the sciatic nerve, lumbar spinal cord and stomach of 12-week diabetic rats, there is a significant reduction of SPLI content. ALCAR treatment prevented SPLI loss in these tissues. Sciatic nerves showed the typical sorbitol increase and myo-inositol loss that were significantly counteracted by ALCAR. This study suggests that ALCAR treatment prevents diabetes-induced sensory neuropathy by improving altered metabolic pathways such as polyol activity and myo-inositol synthesis, and by preventing the reduction of synthesis and axonal transport of substance P.

Neuropeptide content of lungs from asthmatic and nonasthmatic patients.

Tracheal and lung parenchymal SP-LI (substance P-like immunoreactivity) and VIP-LI (vasoactive intestinal peptide-like immunoreactivity) content was measured in HPLC-purified tissue extracts from patients with and without asthma. We detected significantly less SP-LI in tracheal tissue from asthmatic than from nonasthmatic patients, whereas parenchymal SP-LI content was not significantly different between these groups. This finding does not support the concept that asthmatic lungs contain excessive amounts of SP. Indeed, lower SP-LI content of tracheal tissues from asthmatic patients may reflect augmented SP release followed by degradation. We detected greater quantities of VIP-LI in tracheal than in parenchymal tissue in both groups, but did not detect significant differences in VIP-LI content in tracheal or parenchymal tissues from asthmatic and nonasthmatic patients. These findings indicate that asthmatic and nonasthmatic lungs contain similar levels of VIP.

Effect of neonatal hypoxia-ischemia on nigro-striatal dopamine receptors and on striatal neuropeptide Y, dynorphin A and substance P concentrations in rats

Perinatal hypoxic-ischemic brain injury was induced in 7- to 8-day-old rats by ligating the left carotid artery with subsequent exposure to 9% oxygen atmosphere for 2.5 h. The animals were killed 7 days later and grouped according to the degree of brain injury sustained after hypoxia-ischemia. Total protein content measured in striatum ipsilateral to the ligation, and dissected from brains showing extensive damage, was reduced to 64% of contralateral tissue. The protein content was not altered in other groups including control animals exposed to air and in sham-operated animals exposed to hypoxic conditions. The concentration of (pg/mg protein) and total (pg/striatum) striatal dynorphin A-like immunoreactivity (DLI) from brains with extensive damage were increased to 481% and 285% of the contralateral side, respectively. Hypoxia-ischemia increased striatal neuropeptide Y-like immunoreactivity (NPYLI) concentration from brains with extensive damage to 157% of contralateral side, but when the results were expressed as total NPYLI content per striatum, NPYLI content in striatum with extensive damage remained unaltered. Substance P-like immunoreactivity (SPLI) concentration and total content per striatum from brains with extensive damage were reduced to 66% and 43% of the contralateral side, respectively. D 1 and D 2 receptor density in animals killed 10 days after injury was reduced by 24% and 22% of control, respectively, in striatum from brains with extensive damage. These results indicate complex changes in brain neuropeptides following neonatal hypoxia-ischemia. Damage in the substance P system could have functional effects on dopaminergic transmission while the increase in NPYLI and in DLI concentrations may respectively reflect the relative preservation from neuronal damage and possibly an increase in neuropeptide synthesis or decrease in release. The decrease in SPLI concentration and the increase DLI concentration induced by hypoxia-ischemia suggests that these peptides may be present in separate neurons.

Bilateral changes of substance P-, neurokinin A-, calcitonin gene-related peptide- and neuropeptide Y-like immunoreactivity in rat knee joint synovial fluid during acute monoarthritis

It has been hypothetised that the nervous system contributes to the symmetrical response in rheumatoid arthritis. In order to elucidate this, the bilateral concentrations of substance P-like immunoreactivity (SP-LI), neurokinin A-LI (NKA-LI), calcitonin gene-related peptide-LI (CGRP-LI) and neuropeptide Y-LI (NPY-LI) in rat synovial fluid during acute monoarthritis were studied. Equal volumes (0.05 ml) of either Freund adjuvans, carrageenan 2%, substance P 10 −5 M or human recombinant interleukin-1α were injected into the right and saline into the left knee joint. Control rats were given saline bilaterally. Perfusates were obtained from both knees simultaneously at 2, 6 and 24 h after injection and were analysed by specific radioimmunoassays. Increase of SP-, NKA-, CGRP-and NPY-LI in synovial fluid occurred in both knees after injections with the pro-inflammatory substances into the right joints as compared to controls, except for unchanged SP-LI in the right knee joint after 24 h following hrIL-1α injection. There was, however, generally no significant difference in the peptide contents between the right knee (injected with pro-inflammatory substance) as compared to the left knee (given saline) at 2, 6 or 24 h after injection except at three occasions. The results show that experimentally induced monoarthritis induces bilateral changes in synovial fluid peptide content.

Structural characterization of tachykinins (neuropeptide γ, neurokinin A, and substance P) from a reptile, Alligator mississipiensis

An extract of the whole brain of the alligator ( Alligator mississipiensis) contained very high concentrations of substance P-like immunoreactivity (405 pmol/g wet tissue) and neurokinin A-like immunoreactivity (514 pmol/g), as measured with antisera raised against the mammalian peptides. The primary structure of alligator substance P was established as: Arg-Pro-Arg-Pro-Gln-Gln-Phe-Phe-Gly-Leu-Met-NH... This sequence is the same as that of chicken substance P and shows one substitution (Arg for Lys 3) as compared with mammalian substance P. The neurokinin A-like immunoreactivity was separated into two components. Neuropeptide y was the most abundant peptide and its primary structure was established as Asp-Ala-Gly-Tyr-Gly-Gln-Ile-Ser-His-Lys-Arg-His-Lys-Thr-Asp-Ser-Phe-Val-Gly-Leu-Met-NH 2. This sequences shows one substitution (Tyr for His 4) compared with mammalian neuropeptide y. The second component was identical to mammalian neurokinin A. A peptide with the chromatographic properties of mammalian neuropeptide K was not identified in the extract.

Ranakinin: a novel NK1 tachykinin receptor agonist isolated with neurokinin B from the brain of the frog Rana ridibunda.

An extract of the whole brain of the frog Rana ridibunda contained high concentrations of substance P-like immunoreactivity, measured with an antiserum directed against the COOH-terminal region of mammalian substance P and neurokinin B-like immunoreactivity, measured with an antiserum directed against the NH2-terminus of neurokinin B. The primary structure of the substance P-related peptide (ranakinin) was established as: Lys-Pro-Asn-Pro-Glu-Arg-Phe-Tyr-Gly-Leu-Met-NH2. Mammalian substance P was not present in the extract. The primary structure of the neurokinin B-related peptide was established as: Asp-Met-His-Asp-Phe-Phe-Val-Gly-Leu-Met-NH2. This amino acid sequence is the same as that of mammalian neurokinin B. Ranakinin was equipotent with substance P and [Sar9,Met(O2)11]substance P in inhibiting the binding of 125I-Bolton-Hunter-[Sar9,Met(O2)11]substance P, a selective radioligand for the NK1 receptor, to binding sites in rat submandibular gland membranes (IC50 1.6 +/- 0.3 nM; n = 5). It is concluded that ranakinin is a preferred agonist for the mammalian NK1 tachykinin receptor subtype.

Concentrations of neuropeptides substance P, neurokinin A, calcitonin gene-related peptide, neuropeptide Y and vasoactive intestinal polypeptide in synovial fluid of the human temporomandibular joint: A correlation with symptoms, signs and arthroscopicfindings

Arthroscopy was performed on 18 patients (19 joints) with temporomandibular joint arthropathy. Arthroscopic investigation revealed that 12 patients had disk derangement, including 3 patients with rheumatoid arthritis. Six patients had osteoarthrosis, including one patient with rheumatoid arthritis. Synovial fluid content of substance P-like immunoreactivity (SP-LI), neurokinin A (NKALI), calcitonin gene-related peptide (CGRP-LI), neuropeptide Y (NPY-LI) and vasoactive intestinal polypeptide (VIP-LI) were analysed using radioimmunoassay technique. All peptides analysed were found, although in various concentrations, in the different joints. There were no significant differences in concentrations of the peptides in the synovial fluid between patients in the various groups. No significant correlation was found between clinical symptoms and signs, arthroscopic findings, or use of analgesic/anti-inflammatory medication versus concentrations of peptides in the synovial fluid. In comparison with earlier findings in the knee joint significantly higher concentrations of SP-LI, CGRP-LI and NPYLI were found in the TMJ.

Enhanced in vivo release of substance P in the nucleus tractus solitarii during hypoxia in the rabbit: role of peripheral input

In the adult, pentobarbitone-anaesthetized rabbit, the in vivo release of substance P-like immunoreactivity was measured in the nucleus tractus solitarii using microdialysis and radioimmunoassay. Increased (160 ± 16%) extracellular concentrations of substance P-like immunoreactivity were observed during hypoxic provocations of 9% O 2 in N 2 which also resulted in an increase in phrenic nerve activity. In bilateral carotid sinus nerve-denervated animals no enhanced release of substance P was seen in response to hypoxic challenges (105 ± 6%) and the phrenic nerve activity was not significantly affected. Perfusion of the nucleus tractus solitarii region with the dopamine agonist, apomorphine (10 −5 M) resulted in a significant decrease in the extracellular level of substance P. These results provide further evidence that substance P is involved in the mediation of the hypoxic drive inputs from the peripheral chemoreceptors. The interactions of apomorphine with substance P release might also suggest a presynaptic modulation of substance Pergic neurons by dopamine in the nucleus tractus solitarii.

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.

Ethanol-related changes in substance P in the hypothalamus and anterior pituitary

The effect of the administration of a rabbit anti-substance P serum (ASPS) was studied in rats receiving an acute injection of ethanol. ASPS lowered serum prolactin levels and reduced the hyperprolactinemia induced by ethanol. ASPS also decreased LH serum levels in both saline- and ethanol-treated rats. The effect of ethanol on the concentration of substance P-like immunoreactivity (SP-LI) in the mediobasal hypothalamus and the anterior pituitary gland was also investigated. Ethanol reduced SP-LI in the mediobasal hypothalamus but increased it in the anterior pituitary gland. The presence of ethanol (50 mM) did not affect the K +-evoked release of SP-LI from either mediobasal hypothalamus or anterior pituitary gland, though it increased the SP-LI concentration remaining in this gland. These results indicate that ethanol increases the content of SP-LI in the anterior pituitary gland and suggest that substance P may be involved in the prolactin release induced by the acute administration of ethanol.

Axonal transport of substance P-like immunoreactivity in ganglioside-treated diabetic rats

This study examined the effect of treatment of control and streptozotocin-diabetic rats with a mixture of gangliosides, derived from bovine brain, on parameters of axonal transport of substance P-like immunoreactivity (SPLI) and its levels in sciatic nerve and lumbar spinal ganglia. Rats were treated daily (10 mg/kg i.p.) for 28 days and compared with untreated control and diabetic groups. The duration of diabetes was 28 days in both cases. Untreated diabetic rats showed deficits in accumulation of axonally transported SPLI proximal (59% of controls) and distal (34% of controls) to sciatic nerve ligations (left in place for 12 h). Rates of accumulation were unaltered by diabetes. There were small numerical reductions in the SPLI content of unconstricted sciatic nerve and of L 4 and L 5 dorsal root ganglia in diabetic rats. None of these diabetes-associated changes was altered by ganglioside treatment, nor was there any indication of an effect of gangliosides on substance P in non-diabetic rats. The implications are discussed in relation to the possible pathogenesis of diabetic neuropathy.

The distribution of substance P‐containing nerves to the rat small intestine

The concentrations of substance P-like immunoreactivity (SPLI) were measured in mesenteric nerves and vessels of control rats and rats treated with capsaicin during the second day of life. The results showed that there was a significantly higher concentration of SPLI in the jejunum than in the terminal ileum, and that there was a loss of SPLI from these tissues following neonatal treatment with capsaicin. The results suggest that the substance P-containing afferent innervation of the upper small intestine is greater than in the terminal ileum. The significance of these results to the Intensity or Summation hypothesis of visceral pain, and to the thresholds of visceral reflexes from different areas of the small intestine is discussed.

Regional Differences in the Motor and Inflammatory Responses to Capsaicin in Guinea Pig Airways: Correlation with Content and Release of Substance P—like Immunoreactivity

The motor and inflammatory effects of capsaicin, substance P, and neurokinin A, as well as the content and release of substance P-like immunoreactivity (SP-LI), were assessed in the upper and lower guinea pig trachea and in the main bronchus. Capsaicin-induced motor and inflammatory effects were greater in the lower than in the upper tract of the trachea and much more evident at the bronchial than at the tracheal level. On the other hand, no significant regional differences were observed in the potency and efficacy of tachykinins. SP-LI content was significantly greater in the lower than in the upper tract of the trachea and about five times greater in the bronchus than in the trachea. In each single tracheal preparation, a highly significant correlation was found between the motor effect of capsaicin (but not carbachol) and the SP-LI content. Furthermore, capsaicin-induced release of SP-LI was about eight times greater in bronchial than in tracheal tissues. In view of the strict correlation observed between magnitude of motor and inflammatory actions of capsaicin (but not substance P or neurokinin A) and SP-LI content and release, it is proposed that the regional differences in the response of guinea pig respiratory tissues to activation of capsaicin-sensitive sensory fibers might be mainly prejunctional in origin.