Absorption, translocation, and effects of Bt Cry1Ac peptides from transgenic cotton to the intercrops and soil functional bacteria

Insecticidal proteins encoded by the truncated genes from Bacillus thuringiensis (Bt) in transgenic crops are released into soil mainly through root exudate and crop residues. In the present study, Bt Cry1Ac protein was hydrolyzed by pronase that was secreted by the soil bacterium Streptomyces griseus. Six peptides were identified as the products of enzymatic hydrolysis by nano liquid chromatography tandem mass spectrometry (LC-MS/MS). One of the six peptides was labeled with radioactive isotope iodine-125 and then purified. The ¹²⁵I-peptide solution was irrigated to the rhizosphere soil of watermelon seedlings (Citrullus lanatus L.) and wheat seedlings (Triticum aestivum L.), which the two crops usually intercrop with cotton in China. Detection of radioactivity in both plant tissues within one hour proved adsorption, uptake and translocation of the peptide into watermelon and wheat seedlings. Three of the identified peptides were sprayed onto the seedling leaves of watermelon, wheat and maize (Zea mays L.) in the field or the growth chamber. No significant effects on plant growth were observed. These peptides also did not affect growth of organic phosphate-dissolving, nitrogen-fixing, and potassium-dissolving bacteria in the culture. This study provides a new view of GMO risk assessment methodology.

Angiotensin II-induced activation of central AT1 receptors exerts endocannabinoid-mediated gastroprotective effect in rats

The aim of the present study was to analyze whether angiotensin II via the endocannabinoid system can induce gastric mucosal protection, since transactivation of cannabinoid CB1 receptors by angiotensin AT1 receptor in CHO cells was described. Experimental ulcer was induced by acidified ethanol given orally in male Wistar rats, CB1(+/+) wild type and CB1(-/-) knockout mice. The compounds were administered intracerebroventricularly. It was found, that 1. Angiotensin II inhibited the ethanol-induced gastric lesions (11.9-191pmol); the effect of angiotensin II (191pmol) was inhibited by the CB1 receptor inverse agonist AM 251 (1.8nmol) and the inhibitor of diacylglycerol lipase (DAGL), tetrahydrolipstatin (0.2nmol). 2. Angiotensin II exerted gastroprotection in wild type, but not in CB1(-/-) mice. 3. The gastroprotective effect of angiotensin II (191pmol) was reduced by atropine (1mg/kg i.v.) and bilateral cervical vagotomy. In conclusion, stimulation of central angiotensin AT1 receptors via activation of cannabinoid CB1 receptors induces gastroprotection in a DAGL-dependent and vagus-mediated mechanism.

Substance P induces gastric mucosal protection at supraspinal level via increasing the level of endomorphin-2 in rats

The aim of the present study was to analyze the potential role of substance P (SP) in gastric mucosal defense and to clarify the receptors and mechanisms that may be involved in it. Gastric ulceration was induced by oral administration of acidified ethanol in male Wistar rats. Mucosal levels of calcitonin gene-related peptide (CGRP) and somatostatin were determined by radioimmunoassay. For analysis of gastric motor activity the rubber balloon method was used. We found that central (intracerebroventricular) injection of SP (9.3-74 pmol) dose-dependently inhibited the formation of ethanol-induced ulcers, while intravenously injected SP (0.37-7.4 nmol/kg) had no effect. The mucosal protective effect of SP was inhibited by pretreatment with neurokinin 1-, neurokinin 2-, neurokinin 3- and μ-opioid receptor antagonists, while δ- and κ-opioid receptor antagonists had no effect. Endomorphin-2 antiserum also antagonized the SP-induced mucosal protection. In the gastroprotective dose range SP failed to influence the gastric motor activity. Inhibition of muscarinic cholinergic receptors, or the synthesis of nitric oxide or prostaglandins significantly reduced the effect of SP. In addition, centrally injected SP reversed the ethanol-induced reduction of gastric mucosal CGRP content. It can be concluded, that SP may induce gastric mucosal protection initiated centrally. Its protective effect is likely to be mediated by endomorphin-2, and vagal nerve may convey the centrally initiated protection to the periphery, where both prostaglandins, nitric oxide and CGRP are involved in mediating this effect.

Effects of the somatostatin receptor subtype 4 selective agonist J-2156 on sensory neuropeptide release and inflammatory reactions in rodents

BACKGROUND AND PURPOSE

Substance P (SP) and calcitonin gene-related peptide (CGRP) released from capsaicin-sensitive sensory nerves induce local neurogenic inflammation; somatostatin exerts systemic anti-inflammatory actions presumably via sst4/sst1 receptors. This study investigates the effects of a high affinity, sst4-selective, synthetic agonist, J-2156, on sensory neuropeptide release in vitro and inflammatory processes in vivo.

EXPERIMENTAL APPROACH

Electrically-induced SP, CGRP and somatostatin release from isolated rat tracheae was measured with radioimmunoassay. Mustard oil-induced neurogenic inflammation in rat hindpaw skin was determined by Evans blue leakage and in the mouse ear with micrometry. Dextran-, carrageenan- or bradykinin-induced non-neurogenic inflammation was examined with plethysmometry or Evans blue, respectively. Adjuvant-induced chronic arthritis was assessed by plethysmometry and histological scoring. Granulocyte accumulation was determined with myeloperoxidase assay and IL-1beta with ELISA.

KEY RESULTS

J-2156 (10-2000 nM) diminished electrically-evoked neuropeptide release in a concentration-dependent manner. EC50 for the inhibition of substance P, CGRP and somatostatin release were 11.6 nM, 14.3 nM and 110.7 nM, respectively. J-2156 (1-100 microg kg(-1) i.p.) significantly, but not dose-dependently, inhibited neurogenic and non-neurogenic acute inflammatory processes and adjuvant-induced chronic oedema and arthritic changes. Endotoxin-evoked myeloperoxidase activity and IL-1beta production in the lung, but not IL-1beta- or zymosan-induced leukocyte accumulation in the skin were significantly diminished by J-2156.

CONCLUSIONS AND IMPLICATIONS

J-2156 acting on sst4 receptors inhibits neuropeptide release, vascular components of acute inflammatory processes, endotoxin-induced granulocyte accumulation and IL-1beta synthesis in the lung and synovial and inflammatory cells in chronic arthritis. Therefore it might be a promising lead for the development of novel anti-inflammatory drugs.

Changes in tracheo-bronchial sensory neuropeptide receptor gene expression pattern in rats with cisplatin-induced sensory neuropathy

An attenuated neurogenic broncho-constriction underpinned by a decrease in sensory neuropeptide release has been shown to be characteristic of cisplatin-induced neuropathy. The present work was to explore if beyond neuropeptide release, cisplatin at a treatment schedule attaining sensory neuropathy, produced changes in the expression of the receptors of sensory neuropeptides such as somatostatin, calcitonin gene-related peptide (CGRP) and substance P (SP) in bronchial tissue of the rat. Twenty-four Wistar rats were divided into three groups. The animals in the "Treatment groups 1 and 2" were given cisplatin (1.5mgkg(-1)) and mannitol (75mgkg(-1)) over 5 days. The rats in the "Control" group were given mannitol+isotonic saline. Four animals from each group were used to study the expression pattern of the neuropeptide receptors in bronchial tissue. The levels of somatostatin receptor 4 (SSTR 4), neurokinin 1 (NK1), neurokinin 2 (NK2) and CGRP receptor expression were examined by quantitative real time polymerase chain reaction (RT-PCR) method, 11 and 22 days after the last cisplatin/vehicle dose. The cisplatin treatment significantly increased plasma somatostatin immunoreactivity and the expression of SSTR4 receptor detected both on the 11th and 22nd post-treatment days with no change in either CGRP, NK1, and NK2 receptor gene expression or plasma CGRP and substance P levels. We conclude that cisplatin neuropathy is accompanied by an increase in plasma somatostatin immunoreactivity with an increase in SSTR4 expression in rats.

Sumatriptan causes parallel decrease in plasma calcitonin gene-related peptide (CGRP) concentration and migraine headache during nitroglycerin induced migraine attack

Sumatriptan-induced changes in plasma calcitonin gene-related peptide (CGRP) concentration and headache intensity were investigated in 19 female migraineurs during nitroglycerin-induced migraine attack. Sumatriptan nasal spray was administered 120 min after the onset of the attack. Blood samples were obtained immediately before and 60 min after sumatriptan administration. In those subjects whose migraine attack improved considerably 60 min after the treatment the plasma CGRP concentration decreased significantly (P<0.05). In contrast, plasma CGRP concentration failed to change in patients whose headache did not improve. In addition, plasma CGRP concentrations showed significant positive correlations with the headache scores both 60 and 120 min after sumatriptan administration (P<0.05). According to our results plasma CGRP concentration decreases parallel to headache intensity during sumatriptan treatment and this decrease in CGRP predicts effectiveness of antimigraine drug therapy. This supports that one of the main effects of triptans is to decrease CGRP release.

Sensory nitrergic meningeal vasodilatation and non-nitrergic plasma extravasation in anaesthesized rats

The aim of the present study was to evaluate the role of nitric oxide (NO) of sensory neural origin in neurogenic inflammatory response in the trigeminovascular system. Antidromic vasodilatation and plasma extravasation in response to electrical stimulation (15 V, 5 Hz, 0.5 ms, 100 impulses) of the trigeminal ganglion were investigated in the dura mater and nasal mucosa/upper eyelid by laser Doppler flowmetry and [(125)I]-labelled bovine serum albumin, respectively. Electrical stimulation of the trigeminal ganglion of rats elicited a reproducible ipsilateral enhancement of both meningeal and nasal mucosal blood flow. N(omega)-nitro-L-arginine (L-NNA; 4, 8, and 16 mg/kg, i.v.), a nonselective inhibitor of nitric oxide synthase (NOS), inhibited antidromic vasodilatation both in the dura mater (15.86+/-2.05%, 22.82+/-2.51%, and 36.28+/-4.37%) and nasal mucosa (35.46+/-8.57%, 58.72+/-9.2%, and 89.99+/-8.94%) in a dose-dependent manner. Specific inhibitors of neuronal NOS, 7-nitroindazole (7-NI; 20 mg/kg, i.v.) and 3-bromo-7-nitroindazole (3Br-7NI; 10 mg/kg, i.v.) were administered to assess the possible role of NO released from the trigeminal sensory fibres. The meningeal vasodilatation was inhibited by both 3Br-7NI and 7-NI (63.36+/-7.7% and 49+/-6.5%, respectively). The nasal hyperaemic response was also reduced by 3Br-7NI (78.26+/-8.7%). Plasma extravasation in the dura mater and upper eyelid evoked by electrical stimulation of the trigeminal ganglion (25 V, 5 Hz, 0,5 ms, 5 min), expressed as extravasation ratios (ERs) of the stimulated vs. nonstimulated sides, was 1.80+/-0.8 and 4.63+/-1.24, respectively. This neurogenic oedema formation was not inhibited by neither L-NNA nor 3Br-7NI. It is concluded that neural nitrergic mechanisms are involved in the meningeal vasodilatation evoked by electrical stimulation of the trigeminal ganglion.

Decreased sensory neuropeptide release in isolated bronchi of rats with cisplatin-induced neuropathy

We studied if attenuated neurogenic bronchoconstriction was associated with a change in sensory neuropeptide release in preparations from rats with cisplatin-induced neuropathy. Electrical field stimulation (100 stimuli, 20 V, 0.1 ms, 20 Hz) induced an increase in the release of somatostatin, calcitonin gene-related peptide (CGRP) and substance P determined by radioimmunoassay from baseline 0.18+/-0.01, 0.17+/-0.01 and 0.86+/-0.02, to 0.59+/-0.02, 1.77+/-0.04 and 5.96 fmol/mg wet tissue weight, respectively, in organ fluid of tracheal tubes from rats. This was significantly attenuated to post-stimulation values of 0.36+/-0.02, 0.45+/-0.02, 4.68+/-0.24 fmol/mg wet tissue weight for somatostatin, CGRP, and substance P, respectively, with a significant decrease in field stimulation-induced contraction of bronchial preparations from animals 11 days after a 5-day treatment period with cisplatin (1.5 mg/kg i.p. once a day). The cisplatin-treated animals developed sensory neuropathy characterized by a 40% decrease in femoral nerve conduction velocity. The results show that a decrease in tracheo-bronchial sensory neuropeptide release associates with feeble bronchomotor responses in rats with cisplatin-induced sensory neuropathy.

Distribution of PACAP-38 in the central nervous system of various species determined by a novel radioimmunoassay

Pituitary adenylate cyclase activating polypeptide (PACAP) occurs in two molecular forms: PACAP-38 and PACAP-27. Soon after the isolation and chemical characterization of PACAP, the first radioimmunoassay (RIA) methods have been developed, but it is a still rarely used laboratory technique in the field of PACAP research. The aim of the present study was to develop a novel, highly specific PACAP-38 assay to investigate the quantitative distribution of PACAP-38 in the central nervous system of various vertebrate species under the same technical and experimental conditions. Different areas of the brain and the spinal cord were removed from rats, chickens and fishes and the tissue samples were processed for PACAP-38 RIA. Our results indicate that the antiserum used in the RIA is C-terminal specific, without affinity for other members of the vasoactive intestinal polypeptide (VIP)/secretin/glucagon peptide family. The average ID50 value was 48.6+/-3.4 fmol/ml determined in 10 consecutive assays. Detection limit for PACAP-38 proved to be 2 fmol/ml. PACAP-38 immunoreactivity was present in the examined brain areas of each species studied, with highest concentration in the rat diencephalons. High levels of PACAP-38 were also detected in the rat telencephalon, followed by spinal cord and brainstem. The central nervous system of the fish also contained considerable concentrations of PACAP-38, whereas lowest concentrations were measured in the central nervous system of the chicken.

Antiinflammatory and analgesic effects of somatostatin released from capsaicin-sensitive sensory nerve terminals in a Freund's adjuvant-induced chronic arthritis model in the rat

OBJECTIVE

We previously demonstrated that somatostatin (SOM) released from the activated peripheral terminals of capsaicin-sensitive primary sensory neurons inhibits acute inflammation and nociception. This study was undertaken to examine this systemic "sensocrine" function of neuronally derived somatostatin in chronic inflammation in the Freund's complete adjuvant (CFA)-induced arthritis model.

METHODS

Arthritis of the tibiotarsal joint of Lewis rats was evoked by subcutaneous injection of CFA into the left hind paw and the tail root. For 3 weeks, the volume of the paws was measured by plethysmometry, and the mechanonociceptive thresholds were measured by esthesiometry. Plasma concentrations of SOM were determined by radioimmunoassay, and histologic studies of the joints were performed. To impair the function of capsaicin-sensitive afferents, the capsaicin receptor (VR1/TRPV1) agonist resiniferatoxin (RTX) was injected subcutaneously (30, 70, and 100 microg/kg on 3 subsequent days) 7 days before CFA administration. The SOM receptor antagonist cyclosomatostatin (c-SOM; 20 microg/kg) or, in another group, the synthetic heptapeptide agonist TT-232 (2 x 50-400 microg/kg) was administered intraperitoneally every day.

RESULTS

RTX pretreatment or c-SOM injection significantly increased edema and mechanical hyperalgesia of both CFA-treated and contralateral paws. The histologic score based on synovial thickening, cell infiltration, cartilage destruction, and bone erosion was also significantly higher both in the RTX- and the c-SOM-injected groups. These parameters were dose-dependently decreased by TT-232. Plasma SOM-like immunoreactivity increased 4-fold on the twenty-first day, and was inhibited by RTX pretreatment, as well as by daily administration of TT-232.

CONCLUSION

Our data suggest that SOM released into the circulation from capsaicin-sensitive afferents in response to prolonged activation exerts systemic antiinflammatory and analgesic effects. TT-232 can open new perspectives in the treatment of chronic arthritis.

NO-induced migraine attack: strong increase in plasma calcitonin gene-related peptide (CGRP) concentration and negative correlation with platelet serotonin release

The aim of the present study was to investigate changes in the plasma calcitonin gene-related peptide (CGRP) concentration and platelet serotonin (5-hydroxytriptamine, 5-HT) content during the immediate headache and the delayed genuine migraine attack provoked by nitroglycerin. Fifteen female migraineurs (without aura) and eight controls participated in the study. Sublingual nitroglycerin (0.5 mg) was administered. Blood was collected from the antecubital vein four times: 60 min before and after the nitroglycerin application, and 60 and 120 min after the beginning of the migraine attack (mean 344 and 404 min; 12 subjects). In those subjects who had no migraine attack (11 subjects) a similar time schedule was used. Plasma CGRP concentration increased significantly (P<0.01) during the migraine attack and returned to baseline after the cessation of the migraine. In addition, both change and peak, showed significant positive correlations with migraine headache intensity (P<0.001). However, plasma CGRP concentrations failed to change during immediate headache and in the subjects with no migraine attack. Basal CGRP concentration was significantly higher and platelet 5-HT content tended to be lower in subjects who experienced a migraine attack. Platelet serotonin content decreased significantly (P<0.01) after nitroglycerin in subjects with no migraine attack but no consistent change was observed in patients with migraine attack. In conclusion, the fact that plasma CGRP concentration correlates with the timing and severity of a migraine headache suggests a direct relationship between CGRP and migraine. In contrast, serotonin release from platelets does not provoke migraine, it may even counteract the headache and the concomitant CGRP release in this model.

Inhibitory effect of anandamide on resiniferatoxin-induced sensory neuropeptide release in vivo and neuropathic hyperalgesia in the rat

Anandamide (AEA) is an endogenous cannabinoid ligand acting predominantly on the cannabinoid 1 (CB(1)) receptor, but it is also an agonist on the capsaicin VR(1)/TRPV(1) receptor. In the present study we examined the effects of AEA and the naturally occurring cannabinoid 2 (CB(2)) receptor agonist palmitylethanolamide (PEA) on basal and resiniferatoxin (RTX)-induced release of calcitonin gene-related peptide (CGRP) and somatostatin in vivo. Since these sensory neuropeptides play important role in the development of neuropathic hyperalgesia, the effect of AEA and PEA was also examined on mechanonociceptive threshold changes after partial ligation of the sciatic nerve. Neither AEA nor PEA affected basal plasma peptide concentrations, but both of them inhibited RTX-induced release. The inhibitory effect of AEA was prevented by the CB(1) receptor antagonist SR141716A. AEA abolished and PEA significantly decreased neuropathic mechanical hyperalgesia 7 days after unilateral sciatic nerve ligation, which was antagonized by SR141716A and the CB(2) receptor antagonist SR144528, respectively. Both SR141716A and SR144528 increased hyperalgesia, indicating that endogenous cannabinoids acting on CB(1) and peripheral CB(2)-like receptors play substantial role in neuropathic conditions to diminish hyperalgesia. AEA and PEA exert inhibitory effect on mechanonociceptive hyperalgesia and sensory neuropeptide release in vivo suggesting their potential therapeutical use to treat chronic neuropathic pain.

Role of voltage-gated cation channels and axon reflexes in the release of sensory neuropeptides by capsaicin from isolated rat trachea

In order to reveal the role of axon reflexes and sensory receptors in sensory neuropeptide release in response to capsaicin, liberation of substance P, calcitonin gene-related peptide and somatostatin from isolated rat tracheae was investigated in the presence of voltage-sensitive Na(+) and Ca(2+) channel blocking agents. Neuropeptide release induced by capsaicin (10 nM) remained unchanged in the presence of 25 mM lidocaine, 1 microM tetrodotoxin or the N-type Ca(2+) channel inhibitor, omega-conotoxin GVIA (100-300 nM). Peptide release by 100 pulses of 2 Hz field stimulation was prevented by lidocaine or tetrodotoxin. Omega-agatoxin TK (250 nM) significantly inhibited and Cd(2+) (200 microM) prevented capsaicin-induced neuropeptide release. These results suggest that chemical stimulation-induced neuropeptide release does not involve activation of fast Na(+) channels or N- and P-type voltage-dependent Ca(2+) channels, but contribution of Q-type Ca(2+) channels is possible. Sensory neuropeptides are released by capsaicin from sensory receptors without axon reflexes.

Comparative distribution of VIP in the central nervous system of various species measured by a new radioimmunoassay

Vasoactive intestinal polypeptide (VIP) occurs in high concentrations throughout the gut and the nervous system. The presence of VIP has been shown in a number of species, mainly by immunohistochemistry. The aim of the present study was to develop a new, highly specific VIP radioimmunoassay to investigate the distribution of VIP in the central nervous system of various vertebrate and invertebrate species. Different areas of the brain and spinal cord were removed from rats, chickens, turtles, frogs and fishes. The cerebral ganglia and the ventral ganglionic chain were investigated in the earthworm. The tissue samples were processed for VIP radioimmunoassay. Our results show that the antiserum used in the radioimmunoassay turned to be C-terminal specific, without significant affinity to other members of the VIP peptide family. Detection limit of the assay was 0.1 fmol/ml. Highest concentrations were found in the turtle diencephalon, followed by other brain areas in the turtle and rat. All other brain areas in the examined species contained significant levels of VIP. Immunoreactivity was also shown in the cerebral and ventral ganglia of the earthworm. In summary, our results show comparative quantitative distribution in representative species of the phylogenetic line, using the same experimental conditions.