Delayed cardioprotection by intestinal preconditioning is mediated by calcitonin gene-related peptide

Previous studies have shown that nitric oxide and calcitonin gene-related peptide (CGRP) are involved in mediation of the delayed cardioprotection of ischemic or pharmacological preconditioning, and nitric oxide can evoke the release of CGRP. In the present study, we examined the role of CGRP in nitric oxide-mediated delayed cardioprotection by brief intestinal ischemia in rats. The serum concentration of creatine kinase and infarct size were measured after 45-min coronary artery occlusion and 180-min reperfusion. Ischemic preconditioning was induced by six cycles of 4-min ischemia and 4-min reperfusion of the small intestine. Pretreatment with intestinal ischemic preconditioning for 24, 48, or 72 h significantly reduced infarct size and creatine kinase release, and the effects of ischemic preconditioning were completely abolished by L-nitroarginine methyl ester (L-NAME, 10 mg/kg, i.p.), an inhibitor of nitric oxide synthase, or by pretreatment with capsaicin (50 mg/kg, s.c.), which selectively depletes transmitters in capsaicin-sensitive sensory nerves. Intestinal preconditioning caused a significant increase in plasma concentrations of CGRP, and the effect was also abolished by L-NAME or capsaicin. These results suggest that the delayed cardioprotection afforded by intestinal ischemic preconditioning is mediated by endogenous CGRP via the nitric oxide pathway.     

Early and delayed cardioprotection by heat stress is mediated by calcitonin gene-related peptide

Brief ischaemia or heat stress protects the myocardium against ischaemia-reperfusion injury. Heat stimulus evokes release of sensory nerve transmitters, including calcitonin gene-related peptide (CGRP). Since CGRP has been shown to play an important role in the mediation of ischaemic preconditioning, the present study examined whether early or delayed preconditioning induced by retrograde hyperthermic perfusion in vitro or by whole-body hyperthemia in vivo also involves endogenous CGRP. Isolated rat hearts were perfused in the Langendorff mode and subjected to 30 min global ischaemia and 30 min reperfusion. Heart rate, coronary flow, left ventricular pressure and its first derivatives (±dp/dt) were recorded and the CGRP-like immunoreactivity (CGRP-LI) content and the release of creatine kinase (CK) during reperfusion were measured. Retrograde hyperthermic perfusion (42 °C) for 5 min improved the recovery of cardiac function, decreased the release of CK and elevated the content of CGRP-LI in the coronary effluent. CGRP_8–37 (10^–7 mol/l), a selective CGRP receptor antagonist, abolished the cardioprotection by heat stress. Pretreatment with capsaicin (50 mg/kg s.c.), which specifically depletes sensory nerve transmitter content, abolished both the cardioprotection and the increased release of CGRP-LI. Whole-body hyperthermia (42 °C for 15 min) caused an increase in the plasma concentration of CGRP-LI. Early or delayed protection was shown in the hearts obtained from the animals subjected to whole-body hyperthermia 10 min or 48 h before the experiments. The early or delayed protection by heat stress was also abolished by pretreatment with capsaicin. The present study suggests that, in the rat, the early and delayed cardioprotection induced by heat stress involves endogenous CGRP. Received: 31 December 1998 / Accepted: 6 April 1999     

Monophosphoryl lipid A-induced delayed preconditioning is mediated by calcitonin gene-related peptide

The delayed preconditioning of the heart by monophosphoryl lipid A is mediated by endogenous nitric oxide (NO), and the cardioprotection afforded by nitroglycerin is related to stimulation of calcitonin gene-related peptide (CGRP) release. The objective of this study was to explore whether improvement of preservation with cardioplegia by monophosphoryl lipid A is mediated by CGRP. In addition, we examined the effect of monophosphoryl lipid A on the tumor necrosis factor-alpha (TNF-alpha) content of myocardial tissues. The isolated rat heart was perfused in the Langendorff mode. Heart rate, coronary flow, left-ventricular pressure, and its first derivatives (+/-dp/dt(max)) were recorded, and plasma levels of NO and CGRP, the release of creatine kinase in coronary effluent and the content of TNF-alpha in myocardial tissues were measured. Hypothermic ischemia for 4 h caused a decline in cardiac function, and an increase in the release of creatine kinase and in the content of TNF-alpha. Pretreatment with monophosphoryl lipid A (500 microg/kg, i.p.) for 24 h improved the recovery of cardiac function and reduced the release of creatine kinase concomitantly with a decrease in the content of cardiac TNF-alpha. Monophosphoryl lipid A markedly increased plasma concentrations of CGRP and NO. After pretreatment with L-nitroarginine methyl ester (L-NAME), the cardioprotection and the increased release of NO and CGRP induced by monophosphoryl lipid A were abolished. Capsaicin also abolished the cardioprotection and the increased release of CGRP induced by monophosphoryl lipid A, but did not affect the content of NO. The results suggest that monophosphoryl lipid A-induced preconditioning enhances preservation with cardioplegia and that the protective effects of monophosphoryl lipid A are related to stimulation of CGRP release.     

Endopeptidase-24.11 cleaves a chemotactic factor from alpha-calcitonin gene-related peptide.

The sequence of rat alpha-calcitonin gene-related peptide (CGRP-alpha) contains the tetrapeptide eosinophil granulocyte chemotactic factor Val32-Gly-Ser-Glu35. Peptide fragments formed following hydrolysis of rat CGRP-alpha in vitro by endopeptidase-24.11 were identified. The tetrapeptide fragment was generated following cleavage at a substrate recognition site unusual for this enzyme (-Glu-Ala-). Chemotactic activity of rat CGRP-alpha was increased following hydrolysis. Furthermore, rat CGRP-beta, which lacks the tetrapeptide sequence and is completely devoid of chemotactic activity, displayed low but measurable activity after hydrolysis. Val-Gly-Ser-Glu was identified as the principle fragment with chemotactic activity in rat CGRP-alpha. The results show that the chemotactic activity of the neuropeptide rat CGRP-alpha towards eosinophil polymorphonuclear leukocytes is increased following its hydrolysis in vitro by endopeptidase 24.11 through the formation of a previously identified eosinophil chemotactic tetrapeptide.     

Human alpha-calcitonin gene-related peptide (CGRP) is a potent vasodilator in human mesenteric vasculature.

1. The effect of human alpha-calcitonin gene-related peptide (CGRP) and sodium nitroprusside have been measured on human isolated mesenteric vasculature and on rings of human superior mesenteric artery and saphenous vein. 2. When noradrenaline (10(-5) M) was used as the vasoconstrictor in preparations perfused with Krebs solution at constant flow, human alpha-CGRP was 10 times more potent than sodium nitroprusside in evoking dose-dependent falls in perfusion pressure. 3. Human alpha-CGRP and sodium nitroprusside were about equipotent at relaxing rings of superior mesenteric artery contracted by noradrenaline (10(-6) M). When the tone of saphenous vein rings was raised by noradrenaline (10(-6) M), human alpha-CGRP did not relax the vascular smooth muscle. 4. The results show that human alpha-CGRP is a potent vasodilator in human arterial preparations and may act preferentially on arterioles rather than large arteries.     

降钙素基因相关肽介导硝酸甘油增强心停搏液的保护作用(英文)

目的:研究硝酸甘油增强心停搏液的保护作用与促进降钙素基因相关肽释放的关系。方法:在StThomas Hospital心停搏液条件下,离体心脏低温缺血4h后再灌40min,记录心率、冠脉流量及心功能,并测定灌注液中降钙素基因相关肽(CGRP)的浓度及肌酸激酶(CK)的释放量。结果:硝酸甘油(0.1或1μmol/L)改善心功能,降低CK释放,同时促进CGRP的释放。CGRP(5或10nmol/L)也改善心功能及降低CK释放。预先用辣椒素耗竭感觉神经递质后。硝酸甘油的心肌保护和升高灌注液中CGRP浓度作用消失。选择性CGRP受体拮抗剂CGRP_(8-37)也能取消硝酸甘油的心肌保护作用。格列苯脲对硝酸甘油和CGRP的心保护作用均无影响。结论:硝酸甘油增强心停搏液的保护作用是通过内源性CGRP所介导,其保护作用与ATP敏感的钾通道无关。     

Involvement of alpha-calcitonin gene-related peptide in heat stress-induced delayed preconditioning in rat hearts

1. Previous studies have shown that hyperthermia is capable of activating capsaicin-sensitive sensory nerves and stimulating the release of neurotransmitters from their peripheral terminals. Calcitonin gene-related peptide (CGRP) has recently been found to participate in delayed cardioprotection in rat isolated hearts. 2. The purpose of the present study was to explore whether the delayed cardioprotection by heat stress in vivo involves the expression and release of CGRP. 3. Sprague-Dawley rats were pretreated with whole-body hyperthermia (rectal 42 degrees C) for 15 min, 24 h before the experiments and then the left main coronary artery of rat hearts was subjected to a 45 min occlusion followed by 3 h reperfusion. The degree of myocardial injury was evaluated by measurement of infarct size and plasma creatine kinase (CK) activity. The plasma levels of CGRP and expression of CGRP (alpha and beta isoforms) mRNA in lumbar dorsal root ganglia at 4, 8, 16 or 24 h after heat stress treatment were measured. 4. Pretreatment with hyperthermia significantly reduced infarct size and CK release. Heat stress also significantly increased plasma concentrations of CGRP and the expression of alpha-CGRP mRNA, but not beta-CGRP mRNA. The effect of heat stress was completely abolished by pretreatment with capsaicin (50 mg/kg, s.c.), which selectively depletes transmitters in capsaicin-sensitive sensory nerves. 5. In summary, the results suggest that the delayed cardioprotection by heat stress involves the synthesis and release of CGRP and that the protection is mainly mediated by the alpha-CGRP isoform.     

Involvement of alpha-calcitonin gene-related peptide in monophosphoryl lipid A-induced delayed preconditioning in rat hearts

Recent study has shown that monophosphoryl lipid A-induced delayed preconditioning enhanced preservation with cardioplegia and that the protective effects of monophosphoryl lipid A were related to stimulation of calcitonin gene-related peptide (CGRP) release. The purpose of the present study was to explore whether the elevated release of CGRP induced by monophosphoryl lipid A is secondary to stimulation of CGRP synthesis via the nitric oxide (NO) pathway and to characterize the isoform of CGRP. Sprague-Dawley rats were pretreated with monophosphoryl lipid A 24 h before the experiment, and then the left main coronary artery of rat hearts was subjected to 1 h occlusion followed by 3 h reperfusion. Infarct size, plasma creatine kinase activity, the plasma level of CGRP, and the expression of CGRP isoforms (alpha- and beta-CGRP) mRNA in lumbar dorsal root ganglia were measured. Pretreatment with monophosphoryl lipid A (500 microg/kg, i.p.) significantly reduced infarct size and creatine kinase release. Monophosphoryl lipid A caused a significant increase in the expression of alpha-CGRP mRNA, but not of beta-CGRP mRNA, concomitantly with an increase in plasma concentrations of CGRP, and the increased level of CGRP expression happened before stimulation of CGRP release. The effect of monophosphoryl lipid A was completely abolished by pretreatment with L-nitroarginine methyl ester (L-NAME, 10 mg/kg, i.p.), an inhibitor of NO synthase or capsaicin (50 mg/kg, s.c.), which selectively depletes transmitters in capsaicin-sensitive sensory nerves. The results suggest that the delayed cardioprotection afforded by monophosphoryl lipid A involves the synthesis and release of CGRP via the NO pathway, and that the protection is mainly mediated by the alpha-CGRP isoform.     

降钙素基因相关肽对大鼠小肠缺血预适应的保护作用

目的探讨降钙素基因相关肽(CGRP)在大鼠小肠缺血预适应中的作用及意义。方法①健康Wistar雄性大鼠,体质量(280±30)g,分为3组(各8只),对照组(CON):仅分离肠系膜上动脉(SMA),不夹闭,观察90 min;缺血再灌组(I/R):分离SMA,夹闭30 min,再灌注60 min,结束实验;缺血预适应组(IP):分离SMA,夹闭SMA 5 min反复3次,然后再夹闭30 min,再灌注60 min,结束实验。②利用放射免疫法测定CGRP含量,以乳酸脱氢酶(LDH)、丙二醛(MDA)含量变化和形态学变化为指标,评价缺血再灌注损伤。结果缺血预适应可明显抑制大鼠小肠缺血再灌注损伤后LDH的水平增高,降低MDA的含量(P<0.01),保护小肠黏膜不受损伤。结论CGRP为大鼠小肠缺血再灌注损伤中关键性介质之一,缺血预适应可提高大鼠小肠缺血再灌注后CGRP的水平,对抗缺血再灌注损伤。     

Synergistic internal carotid vasodilator effects of human alpha-calcitonin gene-related peptide and nimodipine in conscious rats.

1. In a first series of experiments, male Long Evans rats were chronically instrumented for the measurement of internal carotid blood flow and systemic arterial blood pressure; cardiovascular changes were assessed during and after 30 min infusions of human alpha-calcitonin gene-related peptide (CGRP) (0.06 and 0.6 nmol h-1), or nimodipine (60 and 600 nmol h-1) or human alpha-CGRP plus nimodipine. The effects of human alpha-CGRP or nimodipine on internal carotid vasoconstriction induced by endothelin-1 were also measured. 2. Human alpha-CGRP (0.06 nmol h-1) caused a small (+15%), transient increase in internal carotid blood flow and a tachycardia (+33 beats min-1), but no change in mean blood pressure. Nimodipine (60 nmol h-1) caused a brief internal carotid hyperaemia (+16%) but no changes in blood pressure or heart rate. However, concurrent administration of human alpha-CGRP (0.06 nmol h-1) and nimodipine (60 nmol h-1) caused a sustained increase in internal carotid blood flow (+40%) unaccompanied by significant changes in heart rate or blood pressure. 3. Human alpha-CGRP at a dose of 0.6 nmol h-1 or nimodipine at a dose of 600 nmol h-1 caused substantial reductions in internal carotid vascular resistance (-43 and -40%, respectively); concurrent administration of these doses did not have an additive vasodilator effect.(ABSTRACT TRUNCATED AT 250 WORDS)     

降钙素基因相关肽介导的药物药理学效应

降钙素基因相关肽(CGRP)是感觉神经纤维释放的主要神经递质,广泛分布于中枢和外周组织。在心血管系统,CGRP除了强效舒血管作用外,还能保护缺血心肌,减轻心脏重构。硝酸甘油的抗心绞痛作用及吴茱萸次碱的降压作用和减轻心脏重构作用均与促进CGRP合成与释放有关。在胃肠道,CGRP参与胃肠功能的调节并能减轻胃黏膜损伤,吴茱萸次碱、辣椒素及其衍生物通过促进CGRP的合成和释放对多种因素诱导的胃黏膜损伤具有保护作用。     

The cardioprotective effects of nitroglycerin-induced preconditioning are mediated by calcitonin gene-related peptide

Previous investigations have shown that endogenous calcitonin gene-related peptide (CGRP) may play an important role in the mediation of ischemic preconditioning and that nitroglycerin evokes the release of CGRP. In the present study, we examined whether nitroglycerin provides a preconditioning stimulus, and whether the cardioprotective effects of nitroglycerin-induced preconditioning involve endogenous CGRP. Thirty minutes of global ischemia and 30 min of reperfusion caused a significant impairment of cardiac contractile function and an increased release of creatine kinase. Pretreatment with nitroglycerin at the concentration of 3x10(-7) or 10(-6) M for 5 min produced a significant improvement of cardiac function and a decrease in the release of creatine kinase. The content of CGRP-like immunoreactivity in coronary effluent was increased during nitroglycerin perfusion. However, the cardioprotection afforded by nitroglycerin was abolished by CGRP-(8-37) (10(-7) M), a selective CGRP receptor antagonist. Pretreatment with capsaicin (50 mg/kg, s.c.), which specifically depletes the transmitter content of sensory nerves, also abolished the protective effects of nitroglycerin and markedly reduced the release of CGRP from the heart during nitroglycerin perfusion. These findings suggest that nitroglycerin-induced preconditioning is related to stimulation of CGRP release in rat hearts.     

The cardioprotection of rutaecarpine is mediated by endogenous calcitonin related-gene peptide through activation of vanilloid receptors in guinea-pig hearts

Previous investigations have shown that calcitonin gene-related peptide (CGRP) protects against myocardial ischemia-reperfusion injury and that rutaecarpine activates vanilloid receptors to evoke CGRP release. In the present study, we examined whether rutaecarpine enhances preservation with cardioplegia in guinea-pig hearts, and whether the protective effects of rutaecarpine are related to stimulation of endogenous CGRP release via activating vanilloid receptors. The isolated guinea-pig heart was arrested using St. Thomas Hospital solution, and then reperfused with normothermic Krebs-Henseleit solution for 30 min after a 4-h hypothermic ischemic period. Hypothermic ischemia caused a decline in cardiac function (left ventricular pressure, +/-dp/dt(max), heart rate and coronary flow) and an increased release of creatine kinase during reperfusion. Rutaecarpine at the concentration of 1.0 microM significantly improved the recovery of cardiac function and reduced the release of creatine kinase during reperfusion after hypothermic ischemia. Rutaecarpine at the concentration of 3.0 microM significantly reduced the release of creatine kinase and increased the coronary flow, but only caused a slight improvement of left ventricular pressure, +/-dp/dt(max), heart rate during reperfusion. The cardioprotective effects of rutaecarpine were abolished by capsazepine, a competitive vanilloid receptor antagonist, or by CGRP (8-37), a selective CGRP receptor antagonist. Rutaecarpine at the concentration of 1.0 or 3.0 microM significantly increased the release of CGRP, which was also abolished by capsazepine. These results suggest that rutaecarpine enhances preservation with cardioplegia in guinea-pig hearts and that the protective effects of rutaecarpine are due to stimulation of endogenous CGRP release via activating vanilloid receptors.     

Human alpha-calcitonin gene-related peptide stimulates adenylate cyclase and guanylate cyclase and relaxes rat thoracic aorta by releasing nitric oxide.

1. The signal transduction pathway for vasorelaxation induced by human alpha-calcitonin gene-related peptide (human alpha-CGRP) was studied in rat thoracic aortic rings preconstricted with noradrenaline (10(-7) M). 2. Vasorelaxation by human alpha-CGRP was inhibited by haemoglobin (10(-6) M) and methylene blue (10(-5) M) but was unaffected by ibuprofen (10(-5) M). 3. Acetylcholine caused a 16 fold increase in levels of guanosine 3':5'-cyclic monophosphate (cyclic GMP) with levels of adenosine 3':5'-cyclic monophosphate (cyclic AMP) being unaltered. Human alpha-CGRP caused a 12 fold increase in levels of cyclic GMP but, in contrast to acetylcholine, evoked a 2.5 fold rise in levels of cyclic AMP. The rises in cyclic nucleotides evoked by human alpha-CGRP and acetylcholine were dependent on the presence of an intact endothelium. 4. NG-nitro-L-arginine (L-NOARG: 10(-5) M), which inhibits nitric oxide synthetase, inhibited the relaxant response to human alpha-CGRP and cyclic GMP accumulation without affecting the cyclic AMP accumulation. 5. The data presented in this paper suggests that human alpha-CGRP relaxes the rat thoracic aorta by releasing nitric oxide and stimulating guanylate cyclase. The stimulation of adenylate cyclase by human alpha-CGRP probably precedes the activation of nitric oxide synthase but could be unrelated to the relaxant response.     

Proliferative effect of calcitonin gene-related peptide is induced by at least five proteins as identified by proteome profiling

Calcitonin gene-related peptide is a 37 amino acid neuropeptide. Although calcitonin gene-related peptide activates a G-protein-coupled receptor, recent evidence suggests that calcitonin gene-related peptide induces more complex signaling cascades including the activation of MAP kinases [Eur J Pharmacol; 389:125-130 (2000), Neuropeptides; 34:229-233 (2000)]. However, the molecular mechanisms of this activation still remain to be elucidated. For the first time we applied a proteomics approach in order to identify molecular targets of calcitonin gene-related peptide downstream signaling in the neuroblastoma cell line SK-N-MC and identified proteins that changed either their expression, location, or their post-translational modifications in a time-dependent manner after calcitonin gene-related peptide stimulation.     

The depressor and vasodilator effects of rutaecarpine are mediated by calcitonin gene-related peptide

Previous studies have shown that rutaecarpine has depressor and vasodilator effects, and activates vanilloid receptors to evoke calcitonin gene-related peptide (CGRP) release. In the present study, we examined whether the depressor and vasodilator effects of rutaecarpine are related to the stimulation of endogenous CGRP release via activation of vanilloid receptors in rats. Rutaecarpine (30, 100, or 300 microg/kg, i. v.) caused a depressor effect concomitantly with an increase in the plasma concentrations of CGRP in a dose-dependent manner, and the effects of rutaecarpine were abolished by pretreatment with capsaicin (50 mg/kg, s. c.) which depletes neurotransmitters in sensory nerves. In aortic and superior mesenteric arterial rings, rutaecarpine (10 (-7)-10(-5) M) or capsaicin (3 x 10(-9)-3 x 10(-6) M) caused a concentration-dependent vasodilator response, which was significantly attenuated by capsazepine (10(-5) M), a competitive vanilloid receptor antagonist, or by CGRP-(8-37) (10(-6) M), a selective CGRP receptor antagonist. After pretreatment with capsaicin (10(-5) M) for 20 min, vasodilator responses to rutaecarpine were also markedly attenuated. Similarly, pretreatment with rutaecarpine (10(-5) M) for 20 min also attenuated vasodilator responses to capsaicin. These results suggest that the depressor and vasodilator effects of rutaecarpine are related to stimulation of endogenous CGRP release via activation of vanilloid receptors in rats.     

New insights into nitroglycerin effects and tolerance: role of calcitonin gene-related peptide

It has been shown that calcitonin gene-relate peptide plays an extensive role in cardiovascular system. CGRP is a potent vasodilator and plays an important role in mediation of nitroglycerin-induced vascular relaxation. Recently, calcitonin gene-relate peptide is emerging as a potential player in nitroglycerin tolerance. There is increasing evidence that the decreased depressor effect of nitroglycerin in tolerant states is closely related to a decrease in calcitonin gene-relate peptide release. The reduced release of calcitonin gene-relate peptide in nitroglycerin tolerance is associated with the decreased nitroglycerin biotransformation due to the mitochondrial dysfunction. Recent work has been shown that the inhibited activity of mitochondrial isoform of aldehyde dehydrogenase and the upregulation of phosphodiesterase 1A1 are the key factors that lead to the decreased nitroglycerin biotransformation in nitroglycerin tolerance, with a subsequently reduced release of calcitonin gene-relate peptide.     

Regional haemodynamic effects of prolonged infusions of human alpha-calcitonin gene-related peptide in conscious, Long Evans rats.

1. Haemodynamic measurements were made in conscious, Long Evans rats chronically instrumented for the assessment of changes in regional blood flows (renal, mesenteric and hindquarters, or internal and common carotid) and systemic arterial blood pressure and heart rate, before, during and after 3 day infusions of vehicle or human alpha-calcitonin gene-related peptide (CGRP) (1.5 or 15 nmol kg-1 h-1). 2. In animals with renal, mesenteric and hindquarters flow probes (n = 8), during the first day of infusion of human alpha-CGRP (1.5 nmol kg-1 h-1) there was sustained tachycardia and hypotension, a sustained reduction in renal flow, a transient reduction in mesenteric flow and a relatively well-maintained increase in hindquarters flow. All these effects were significantly different from the changes seen in vehicle-infused rats (n = 8), but calculation of vascular conductances showed only the late mesenteric vasodilatation and the sustained hindquarters vasodilatation were different from the changes in vehicle-infused rats. However, by the second day of infusion and thereafter cardiovascular variables in the animals receiving vehicle and those receiving human alpha-CGRP were not different. 3. Nine animals instrumented with probes to monitor changes in internal and common carotid haemodynamics initially received human alpha-CGRP infused at a rate of 1.5 nmol kg-1 h-1. Three of these animals still showed some response to the human alpha-CGRP (tachycardia, hypotension, hyperaemic vasodilatation) throughout the second day of infusion and hence were taken through the 3 day infusion protocol. When the infusion was stopped on the fourth day all these animals showed reversal of the effects of human alpha-CGRP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Delayed preconditioning by cardiac ischemia involves endogenous calcitonin gene-related peptide via the nitric oxide pathway

Previous investigations have shown separately that calcitonin gene-related peptide (CGRP) or nitric oxide (NO) is involved in mediation of ischemic preconditioning. In the present study, we tested interactions of CGRP with NO in mediation of delayed preconditioning. In Sprague-Dawley rats, ischemia-reperfusion injury was induced by 45-min occlusion followed by 3-h reperfusion of coronary artery, and preconditioning was induced by four cycles of 3-min ischemia and 5-min reperfusion. Infarct size, plasma creatine kinase activity, the plasma level of NO and CGRP, and the expression of CGRP mRNA in dorsal root ganglion were measured. Pretreatment with preconditioning significantly reduced infarct size and the release of creatine kinase during reperfusion, and caused a significant increase in the expression of CGRP mRNA, concomitantly with an elevation in the plasma level of CGRP and NO. The effects of preconditioning were completely abolished by administration of L-nitroarginine methyl ester (L-NAME, 10 mg/kg, i.p.), an inhibitor of NO synthase. Pretreatment with capsaicin (50 mg/kg, s.c.), which depletes transmitters in capsaicin-sensitive sensory nerves, also blocked the cardioprotection of preconditioning and reduced the synthesis and release of CGRP, but did not affect the concentration of NO. The present results suggest the delayed protection afforded by ischemic preconditioning is also mediated by endogenous CGRP via the NO pathway in rat heart.     

Enhancement of salivary secretion and neuropeptide (substance P, alpha-calcitonin gene-related peptide) levels in saliva by chronic anethole trithione treatment.

Anethole trithione, a choleretic, has been reported to be effective in the treatment of dry mouth. We have examined the effects of chronic treatment with anethole trithione on salivary secretion, substance P immunoreactive substance (SP-IS) and alpha-calcitonin gene-related peptide immunoreactive substance (alpha-CGRP-IS) concentrations in human saliva. Anethole trithione caused significant increases of saliva SP-IS concentrations from the day 13 (25.3 +/- 1.6 pg mL(-1)) to day 14 (25.8 +/- 1.7 pg mL(-1)) compared with day 1 (19.9 +/- 1.9 pg mL(-1)). Anethole trithione caused significant increase in saliva alpha-CGRP-IS concentration on day 14 (39.9 +/- 4.7 pg mL(-1)) compared with day 1 (27.7 +/- 4.7 pg mL(-1)). Anethole trithione significantly increased the sialosis volumes from day 11 to day 14 (1.6 +/- 0.1-1.7 +/- 0.2 mL) compared with the day 1 (1.2 +/- 0.2 mL). Simple linear regression of the increase in sialosis volume with saliva SP-IS (r = 0.94) and alpha-CGRP-IS (r = 0.97) concentrations was found. These results demonstrated that chronic treatment with anethole trithione affected saliva SP-IS and alpha-CGRP-IS concentration in human saliva and sialosis volume.