PACAP reverses airway hyperresponsiveness induced by ozone exposure in guinea pigs

BACKGROUND

We previously demonstrated that pituitary adenylate cyclase activating peptide (PACAP) inhibits airway smooth muscle contraction and plasma extravasation.

OBJECTIVE

We thus hypothesized that PACAP may regulate airway responsiveness through these effects and examined the effects of exogenously applied PACAP on the airway hyperresponsiveness induced by ozone exposure.

METHODS

Ozone exposure was carried out in awake, spontaneously breathing guinea pigs using 3 ppm for 2 h. Airway responsiveness to histamine was determined before and 30 and 90 min after the termination of ozone exposure for 2 h in anesthetized animals. Extravasation of Evans blue was measured before and 90 min after the termination of ozone exposure. Either PACAP (10(-6) mol/kg) or vehicle was administered intravenously 60 min after exposure. The airway responsiveness was expressed as the concentration of histamine required to produce a 200% increase in total pulmonary resistance (PC(200)).

RESULTS

Ozone exposure caused a significant decrease in PC(200) (n = 5, p < 0.05) 30 min after ozone exposure which persisted 90 min thereafter, thus suggesting that ozone caused airway hyperresponsiveness. PACAP significantly suppressed the increase in airway hyperresponsiveness induced by ozone 90 min after exposure (n = 5, p < 0.05). In contrast, this peptide did not have any effect on plasma extravasation.

CONCLUSION

We thus conclude that PACAP decreases ozone-induced airway responsiveness, and, therefore, intravenously administered PACAP may be useful in reversing airway hyperresponsiveness.

[Diffuse idiopathic skeletal hyperostosis with fibrobullous change in upper lung lobes and dyspnea due to limitation of thoracic cage]

A 48-year-old man was admitted to our hospital because of shortness of breath and abnormal shadows on chest roentgenograms. Although he had been given a diagnosis of ankylosing spondylitis (AS) at the onset of his symptoms, a diagnosis of diffuse idiopathic skeletal hyperostosis (DISH) was made by our orthopedics department on the basis of bone X-ray findings. Spirograms demonstrated a restrictive pattern and residual volume was increased. Total lung capacity and respiratory muscle function were normal, suggesting that the abnormal spirogram findings were due to decreased thoracic cage compliance. Chest roentgenograms and computed tomographic scans showed apical fibrobullous changes in both lungs, similar to those observed in AS. To our knowledge, this is the first case of DISH with pulmonary involvement to be reported to date. The pulmonary manifestations were similar to those of AS, and it was speculated that they were due to limitation of the thoracic cage.

Injection of nicotine into the superior colliculus facilitates occurrence of express saccades in monkeys

To clarify the role of cholinergic inputs to the intermediate layer of the superior colliculus (SC), we examined the effect of microinjection of nicotine into the SC on visually guided saccades in macaque monkeys. After injection of 0.4-2 microl of 1-100 mM nicotine into the SC, frequency of extremely short latency saccades (express saccades; reaction time = 70-120 ms) dramatically increased, for the saccades the direction and amplitude of which were represented at the location of the injection site on the collicular map. However, no marked change was observed for the relationship between the peak velocities and the amplitudes of saccades. These results suggested that activation of nicotinic acetylcholine receptors in the SC can facilitate initiation but causes no major change in dynamics of visually guided saccades.

The characteristics of nocturnal scratching in adults with atopic dermatitis

Patients with atopic dermatitis (AD) are known to suffer from nocturnal itch, and the resultant scratching may worsen the skin lesions. We observed nocturnal scratching for 112 nights in 35 adult patients with AD, using an infrared video camera system. To quantify the amount of scratching, we counted scratching bouts lasting more than 5 s and calculated the duration of all the scratching bouts (total scratching time, TST). The percentage of TST in the total recording time (TST%) was used as an index of nocturnal scratching. Mean +/- SD TST% was 14.3 +/- 13.9 for patients with severe AD, 6.2 +/- 3.7 for those with moderate AD and 0.7 +/- 0.4 for those with mild AD. The higher TST% in the severely affected group was attributed mainly to a longer duration rather than a higher frequency of bouts. Patients scratched more in the first third of the night than in the later two-thirds. Both the group of patients whose disease distribution pattern was generalized and those who showed a head-neck-shoulder type distribution scratched their heads, faces and necks for longer than other parts of the body. Repeated measurement performed on individual subjects resulted in a similar TST% when there was little change in skin lesions. TST% reduced by 15 +/- 21% when the patients showed marked improvement. The measurement of nocturnal scratching helps to evaluate the severity of itch in AD. In addition, the infrared video successfully detected the location and nature of nocturnal scratching in AD.

A case of spinocerebellar ataxia type 6 mimicking olivopontocerebellar atrophy

Spinocerebellar ataxia type 6 (SCA6) is an autosomal dominant, slowly progressive cerebellar ataxia without multisystem involvement. We report a 57-year-old woman with genetically confirmed SCA6 who showed clinical features of olivopontocerebellar atrophy. Conventional T2-weighted and FLAIR MRI demonstrated high signal in the middle cerebellar peduncles, in addition to mild atrophy of the pons and cerebellum.

Hyperosmotic stress-induced reorganization of actin bundles in Dictyostelium cells over-expressing cofilin

BACKGROUND

Cofilin is a low-molecular weight actin-modulating protein, which binds to, severs, and depolymerizes actin filaments in vitro. Aip1, an actin-interacting protein, was recently identified as a product of a gene on a multicopy plasmid which suppresses the temperature-sensitive phenotype of a cofilin mutant in Saccharomyces cerevisiae. Actin cytoskeleton plays an essential role in resistance to hyperosmotic stress in Dictyostelium discoideum. The roles of cofilin and Aip1 in this resistance are not known.

RESULTS

In response to hyperosmotic stress, D. discoideum cells round up. This stress-induced morphological change involves the redistribution of cofilin, together with actin filaments, into cortical contractile portions of the cells, followed by their contraction. Over-expression of cofilin increases and thickens cortical actin bundles in cells. The bundles become tight and are reorganized into a ring-shaped structure in response to hyperosmotic stress. The ring structure of actin bundles had two characteristic bands across them; bright and dark bands, heavily stained and not stained with phalloidin. In the bundles, straight filaments with a diameter of 5.3-nm were aligned parallel by cross-bridge structures. In cells lacking the myosin-II heavy chain, the bundles, which were induced by an over-expression of cofilin, shortened and became straight following hyperosmotic stress, forming a polygonal structure. D. discoideum Aip1/Wrp2 enhanced the severing of actin filaments by cofilin in vitro and colocalized with cofilin in cells, including those that were over-expressing cofilin before and after exposure to hyperosmotic stress.

CONCLUSIONS

Cofilin plays a pivotal role in concert with Aip1/Wrp2 in the reorganization of actin architectures into bundles that contract in a myosin-II-independent manner, in response to hyperosmotic stress.

Role of nitric oxide released from iNANC neurons in airway responsiveness in cats

The precise role of inhibitory nonadrenergic noncholinergic (iNANC) neurons and nitric oxide in airway hyperresponsiveness remains uncertain. The role of NO in the regulation of airway responsiveness was studied in anaesthetized and mechanically ventilated cats. To assess airway responsiveness, the changes in total pulmonary resistance (RL) produced by delivering serotonin aerosol to the airways were measured before and after N(omega)-nitro-L-arginine methyl ester (L-NAME), or a ganglionic blocker, hexamethonium, which has been reported to block iNANC. Serotonin was chosen because it causes bronchoconstriction in part by neural reflex. To further clarify the mechanism(s) involved, the effect of inhaled capsaicin was also determined in animals with sustained bronchoconstriction induced by serotonin after treatment with atropine and propranolol. Inhibition of NO synthase by L-NAME or blockade of iNANC neurons by hexamethonium significantly increased airway responsiveness. However, addition of L-NAME did not further increase airway responsiveness in animals treated with hexamethonium. In the presence of atropine and propranolol, inhaled capsaicin caused a marked bronchodilation during serotonin-induced sustained bronchoconstriction. The bronchodilation induced by capsaicin was significantly suppressed by hexamethonium and by L-NAME. These results suggest that the nitric oxide released from inhibitory nonadrenergic noncholinergic neurons is important in modulating the airway responsiveness of cats in vivo.

[Horner's syndrome in a patient with diffuse malignant pleural mesothelioma]

A 63-year-old man was admitted to our hospital because of left back pain and dysesthesia in his left arm. On physical examination, the patient had ptosis, myosis, and anhydrosis on the left side, suggesting Horner's syndrome. A chest computed tomographic scan disclosed a mass lesion adjoining to the left posterior mediastinum. Although the mass lesion showed a slight decrease in size after the systemic administration of corticosteroids, no further improvement was obtained. Open chest examination revealed extended thickening of the parietal pleura with massive involvement of the upper thoracic sympathetic trunk. The diagnosis was malignant mesothelioma of sarcomatous type. Horner's syndrome is a rare but possible complication in the clinical course of malignant pleural mesothelioma.

Cytokine-induced tendinitis: a preliminary study in rabbits

This study was designed to determine the effects of a single injection of a species-specific preparation of cytokines into rabbit patellar tendons and to compare the results with a known model of tendinitis, the collagenase-injection model. New Zealand White rabbits were divided into two groups and two time periods (4 and 16 weeks) and injected in the midsubstance of the right patellar tendon with either cytokines or collagenase under ultrasound guidance to confirm intratendinous needle placement. The left patellar tendon was injected with 0.025 ml of saline solution and served as a control. The rabbits were returned to cage activity after injection. At death, two rabbits in each group underwent histological analysis; the remaining eight animals in each time frame were evaluated biomechanically and then biochemically with use of the patella/whole patellar tendon/tibia complex. Histologic results at 4 weeks in the tendons injected with cytokines demonstrated increased cellularity, which was resolving by 16 weeks. The matrix appeared unchanged. The tendons injected with collagenase demonstrated increased angiogenesis of the matrix, hypercellularity, and fibrosis around the tendon at 4 weeks. At 16 weeks, myxoid changes, focal fibrosis, and collagen-bundle disarray with persistent increase in cellularity were noted. Biomechanically, a significant decrease in ultimate load at 16 weeks was seen in the tendons injected with cytokines but no change was seen in cross-sectional area. The tendons injected with collagenase demonstrated a significant increase in cross-sectional area at 4 and 16 weeks compared with those injected with cytokines. Biochemically, there was no significant difference in collagen content between the two groups at 4 or 16 weeks but the tendons injected with collagenase demonstrated a significant increase in crosslinking at 16 weeks. Our conclusion is that the tendons injected with the cytokine preparation represent a model of mild, seemingly reversible tendon injury. The cytokine preparation produces no matrix damage or evidence of collagen degradation and is species specific.

[A case of the cerebellar atrophy and pseudo-hyperchloremia as a clue to diagnose chronic bromvalerylurea intoxication]

A 36-year-old woman was admitted to our hospital because of walking disturbance and dizziness. Her neurological examination showed psychiatric disturbance, truncal and limb ataxia, wide-based gait. She has taken 3 g of bromvalerylurea daily. The laboratory test revealed elevated levels of serum chloride (201 mEq/L) and bromide (105 mg/dl), and decreased (-43 mEq/L) anion gap. Brain MRI revealed atrophy of upper part of the vermis and cerebellar hemisphere, and widening of the primary fissure and dilatation of the forth ventricle. Bromvalerylurea, which is an easily available sedative, should be still noted as a cause of cerebellar ataxia. Increased level of serum chloride was useful information for early diagnosis of chronic bromide intoxication.

Effect of inhaled glucocorticoid on the cellular profile and cytokine levels in induced sputum from asthmatic patients

Cytokines are considered to play a role in the airway inflammation of bronchial asthma. We examined the cellular profile and cytokine levels in induced sputum samples obtained before and after treatment with beclomethasone dipropionate (BDP, 800 microg/day, for 4 weeks) in 12 mild to moderate asthmatic subjects who had not previously received inhaled glucocorticosteroids. Sputum was induced with a 20-min inhalation of 3% saline by an ultrasonic nebulizer. The freshly expectorated sputum separated from the saliva was analyzed for cell counts, for the concentration of interleukin-8 (IL-8), and for the concentration of granulocyte-macrophage colony-stimulating factor (GM-CSF). The mean percentage of eosinophils in the sputum samples decreased significantly after BDP treatment, but no significant change in the percentage of neutrophils was observed. The mean IL-8 and GM-CSF levels also decreased significantly after treatment. The BDP treatment was associated with an increase in the mean peak expiratory flow (PEF) and with a decrease in the diurnal variation of PEF. These results suggest that inhaled steroids improve airway inflammation and lung function in asthmatics, presumably in part by inhibiting the synthesis of inflammatory cytokines such as IL-8 and GM-CSF.

ET(A) receptor antagonist ameliorates nephrosclerosis and left ventricular hypertrophy induced in rat by prolonged inhibition of nitric oxide synthesis

We investigated the ability of the ETA receptor antagonist T-0115 and the angiotensin-converting enzyme (ACE) inhibitor imidapril hydrochloride to prevent hypertensive complications induced in rats by chronic inhibition of nitric oxide (NO). Male Wistar rats were given distilled water (control), NG-nitro-L-arginine methyl ester (L-NAME) 500 mg/l, or L-NAME plus imidapril 10 mg/l in the drinking water. In rats treated with L-NAME 500 mg/l plus T-0115, T-0115 was given in the food at a dose of 0.2 mg/g food or 0.6 mg/g food. We then collected 24-h urine samples at 2, 4, and 6 wk, obtained blood samples at 6 wk, and histologically examined the kidney and heart. L-NAME markedly reduced the levels of NO metabolites in serum and urine while increasing the tail-cuff blood pressure, the urinary albumin level (1.90+/-0.65 vs. 0.05+/-0.02 mg/d/100 g in control), and the area of the left ventricular wall (83.3+/-3.0 vs. 69.8+/-1.8 mm2 in control). The plasma renin activity was significantly higher in rats treated with L-NAME than in the control rats. The concomitant administration of T-0115 0.6 mg/g food with L-NAME ameliorated the tail-cuff pressure and the albuminuria (0.56+/-0.23 mg/d/100 g), although to a lesser extent than the changes seen with imidapril 10 mg/l. T-0115 0.6 mg/g food prevented left ventricular hypertrophy as effectively as imidapril 10 mg/l (70.8+/-1.8 with T-0115 vs. 68.3+/-2.7 mm2 with imidapril). Chronic inhibition of NO synthesis produced left ventricular hypertrophy and nephrosclerosis. Our results demonstrate that inhibition of the renin-angiotensin system morely effectively prevents nephrosclerosis than does the blockade of ETA receptors in a model of hypertension induced by chronic NO blockade. However, inhibition of the ET-1 pathway appeared to be as effective as ACE inhibitors in preventing left ventricular hypertrophy in this model.

Molecular cloning of rat klotho cDNA: markedly decreased expression of klotho by acute inflammatory stress

We have recently identified a novel gene, termed klotho, that is involved in the suppression of several aging phenotypes. The gene encodes a membrane protein that shares sequence similarity with the beta-glucosidases of bacteria and plants. In this study, we isolated rat klotho cDNA and examined its tissue distribution in rats. The deduced amino acid sequence of rat Klotho protein was 1014 amino acids in length and 94 and 85% homologous to those of mouse and human Klotho proteins, respectively. Northern blot analysis using the rat klotho cDNA probe identified a single transcript of 5.2 kb in size expressed predominantly in the kidney, while RT-PCR detected low levels of expression also in the brain, lung, intestine, and ovaries. During development, klotho expression in the kidney was markedly augmented after birth. Chromosomal localization of rat klotho was mapped to 12q12. Northern blot analysis showed that expression of klotho was markedly decreased by lipopolysaccharide (LPS) in vivo, suggesting that expression of klotho is affected by acute inflammatory stress. The present study leads to a better understanding of the physiologic and pathophysiologic roles of Klotho.

Contractile protein isoforms of single and cultured smooth muscle cells from guinea pig ileum

Single smooth muscle cells isolated from guinea pig ileum using collagenase and papain produce contractile response to muscarinic agents, while the cultured cells do not. Using fluo-3/AM and a confocal laser scanning fluorescence microscope, it was observed that carbachol, a muscarinic agent, caused an increase in the intracellular Ca2+ of both single and cultured cells. SDS-PAGE and Western Blot analyses revealed the expression of myosin heavy chain isoforms of SM1 (204 kDa) and SM2 (200 kDa) in single smooth muscle cells, and non muscle isoform (196 kDa) of myosin heavy chain only in the cultured cells. With respect to actin isoforms, alpha-actin was predominant in single cells and beta-actin was major in the cultured cells. Two types of tropomyosin monomer, 39 kDa and 41 kDa, were detected in single cells, while the 41 kDa monomer was lost in cultured cells. These differences in contractile protein profiles between single and cultured cells were collaborated with the observation of cells using immunofluorescence microscope with responsible antibodies to isoforms of myosin heavy chain, actin and tropomyosin. These results suggest that the loss of contractility in cultured smooth muscle cells is profoundly related to changes in contractile protein profiles from smooth muscle type to non muscle type.

Role of adrenergic nervous system in cigarette smoke-induced bronchoconstriction in guinea pigs

The goal of this study was to clarify the role of the adrenergic nervous system in bronchoconstriction induced by exposure to cigarette smoke in guinea pigs. Artificially ventilated animals were exposed to 160 puffs of smoke for 8 min. Bronchoconstriction was assessed as a percentage of the baseline total pulmonary resistance (RL). The effects of pretreatment with phentolamine (0.1 mg/kg, i.v.), propranolol (1 mg/kg, i.v.), and/or atropine (1 mg/kg, i.v.) were evaluated. Exposure to cigarette smoke caused significant bronchoconstriction. Phentolamine, an alpha-adrenoceptor antagonist, significantly inhibited cigarette smoke-induced bronchoconstriction, while propranolol, a beta-adrenoceptor antagonist, significantly enhanced it. Combined use of these compounds further enhanced the bronchoconstriction. All of modulations of the bronchoconstriction by adrenoceptor antagonists were completely abolished by pretreatment with atropine. Phentolamine and/or propranolol had no effect on the bronchoconstriction induced by inhaled acetylcholine. Pretreatment with yohimbine (0.5 mg/kg, i.v.), a selective alpha2-adrenoceptor antagonist, showed modulatory effects similar to those of phentolamine on cigarette smoke-induced bronchoconstriction. These results suggest that cigarette smoke-induced bronchoconstriction is regulated by the prejunctional modulation of the cholinergic system via alpha- and beta-adrenoceptors. This mechanism may be modulated by the autoregulation of adrenergic nerves via the alpha2-autoreceptor.

Effects of epinastine hydrochloride on cholinergic neuro-effector transmission in canine tracheal smooth muscle

We determined the effects of epinastine hydrochloride, an anti-asthmatic drug, on cholinergic neuro-effector transmission in canine trachea. Isometric tension of tracheal strips was measured in the presence of indomethacin and propranolol. Epinastine (10(-6) M) significantly suppressed the contraction evoked by electrical field stimulation, but had no effect on the acetylcholine-evoked contraction. An L-type Ca2+ channel blocker, nicardipine, did not suppress the electrical field stimulation-induced smooth muscle contraction and did not alter the inhibitory effect of epinastine. An N-type Ca2+ channel blocker, omega-conotoxin, suppressed the electrical field stimulation-induced contraction in a dose-dependent manner, and in a subthreshold/intermediate concentration abolished the inhibitory effect of epinastine. These findings indicate that epinastine exerts prejunctional inhibitory effects on airway smooth muscle of dogs, presumably by inhibiting acetylcholine release from vagal nerve terminals, and suggest that this effect is mediated by N-type Ca2+ channels.

[Bickerstaff's brainstem encephalitis with one-and-a-half syndrome]

We presented a case of Bickerstaff's brainstem encephalitis. A 50-year-old woman developed semicoma, external ophthalmoplegia, hyporeflexia, extensor plantar responses. A high titer of anti-GQ1b IgG antibody was detected in her acute phase serum. Auditory brainstem response suggested the presence of brainstem lesion. Although MRI and CSF showed no abnormality, one-and-a-half syndrome was observed during the clinical course, suggesting involvement of the pontine tegmentum. She received steroid pulse-therapy and symptoms disappeared completely. Our case suggested that anti-GQ1b IgG antibody might relate to the pathogenesis of intramedullary as well as extramedullary lesions.

Effects of thromboxane A2 antagonist on airway hyperresponsiveness, exhaled nitric oxide, and induced sputum eosinophils in asthmatics

We examined effects of a thromboxane A2 (TXA2) antagonist seratrodast on airway hyperresponsiveness, exhaled nitric oxide (NO), and eosinophils in induced sputum in 14 asthmatics. Subjects were administered 80 mg of seratrodast once a day for 4 weeks. Respiratory conductance (Grs) was measured by the forced oscillation method and airway responsiveness was evaluated as the inhaled dose of methacholine, which induced 35% decrease in Grs. Subjects breathed into a Teflon bag, and NO concentration in the bag was measured by a chemiluminescence analyzer. Induced sputum comprised the entire expectorate produced during a 20 min inhalation of 3% saline, and was analyzed for total and differential cell counts. Airway hyperresponsiveness was significantly decreased by seratrodast. By contrast, no differences in either exhaled NO or percentage of eosinophils in sputum were observed before or after seratrodast. We conclude that seratrodast may attenuate airway hyperresponsiveness, presumably by antagonizing TXA2 released from the inflamed airways.

Downregulation of the Klotho gene in the kidney under sustained circulatory stress in rats

We recently reported the isolation of the klotho gene, which in predominantly expressed in the kidney and involved in human aging phenotypes. In our previous studies, we demonstrated that the Klotho protein or its metabolites may possibly function as humoral factor(s) and protect against endothelial dysfunction because acetylcholine-mediated NO production in arteries was impaired in heterozygous klotho deficient mice (kl/+). However, the pathophysiological significance of the Klotho protein has not been clarified yet. In the present study, we examined expression of the klotho gene in the kidney of the following rat models for human diseases: (1) spontaneously hypertensive rat, (2) deoxycorticosterone acetate-salt hypertensive rat, (3) 5/6 nephrectomized rat, (4) non-insulin-dependent diabetes mellitus rat (the Otsuka Long-Evans Tokushima Fatty rat), and (5) rat with acute myocardial infarction. The expression levels of klotho mRNA in the kidney in these models were significantly lower than controls except for MI rats. This is the first report showing the expression of the klotho gene in the kidney is regulated under sustained circulatory stress such as long-term hypertension, diabetes mellitus, and chronic renal failure.

Eosinophilic airway inflammation induced by repeated exposure to cigarette smoke

Acute exposure to cigarette smoke causes airway hyperresponsiveness (AHR) in guinea-pigs, which resolves within a few hours. Repeated exposure may have a different effect on the airways. To address this question, guinea-pigs were repeatedly exposed to cigarette smoke (six cigarettes for 1 h x day(-1)) for 14 consecutive days. Airway responsiveness to inhaled histamine and differential cell counts in bronchoalveolar lavage fluid (BALF) were evaluated 1 day after the last exposure. Significant neutrophilia in BALF was observed after 3 days of smoke exposure. Significant eosinophilia in BALF and AHR were observed after 14 days of smoke exposure, but not after 3 or 7 days of smoke exposure. These changes persisted until 3 days after the last exposure and resolved 7 days afterwards. Histologically, the recruited eosinophils were observed predominantly in the airways, but not in the alveoli. Treatment with E-6123, a specific platelet-activating factor receptor antagonist (1 mg x kg(-1) x day(-1) p.o. during smoke exposure) significantly inhibited the eosinophil influx and AHR. Repeated exposure to cigarette smoke may induce prolonged airway inflammation and airway hyperresponsiveness in guinea-pigs. Platelet-activating factor or platelet-activating factor-like lipids may play a key role in airway hyperresponsiveness, presumably by the induction of eosinophilic airway inflammation.

Klotho protein protects against endothelial dysfunction

Arteriosclerosis caused by aging is recognized to be a crucial risk factor of cardiovascular disease. We recently established klotho mouse which causes age-related disorders including arteriosclerosis. However, no information on endothelial function of klotho mouse or the physiological role of klotho protein as a circulating factor is available. In this report, we demonstrate that 50% effective dose of aortic relaxation in response to acetylcholine in heterozygous klotho mice is significantly greater (4 x 10(-5) M) than in wild-type mice (8 x 10(-6) M, n = 7, p < 0.05) and that the vasodilator response of arterioles to acetylcholine is significantly attenuated in heterozygous (20% effective dose; 2 x 10(-6) M) and homozygous klotho mice (>1 x 10(-5) M) as compared with wild-type mice (1 x 10(-7) M, n = 7, p < 0.05). Nitric oxide metabolites (NO-2 and NO-3) in urine are significantly lower in heterozygous klotho mice (142 +/- 16 nmol/day) than wild-type mice (241 +/- 28 nmol/day, n = 13, p < 0.05). Parabiosis between wild-type and heterozygous klotho mice results in restoration of endothelial function in heterozygous klotho mice. We conclude that the klotho protein protects the cardiovascular system through endothelium-derived NO production by humoral pathways.

[Airway hyperresponsiveness in bronchial asthma]

Airway hyperresponsiveness to a wide variety of stimuli is a characteristic feature of bronchial asthma. Although its precise mechanism remains uncertain, previous investigations revealed the importance of airway inflammation for the development of airway hyperresponsiveness. Thus, in an experimental animal, the stimuli which induce airway hyperresponsiveness cause airway inflammation simultaneously, and suppression of this airway inflammation attenuates airway hyperresponsiveness. Furthermore, in asthmatic subjects, the level of airway hyperresponsiveness usually correlates with the clinical severity of asthma and medication requirements. Based on these findings, recently, asthma is defined by reversible airway obstruction, airway hyperresponsiveness and airway inflammation. Key concept for management of asthma, therefore, may be focused on monitoring airway inflammation, and on treating this inflammation. In addition to the direct assessment of airway inflammation by induced sputum or exhaled nitric oxide, it can be also reflected by airway hyperresposiveness on peak flow monitoring. For the treatment of asthma, therapeutic interventions with anti-inflammatory agents modify airway hyperresponsiveness, improve asthma symptoms, and reduce the need for frequent use of a bronchodilator.

Pituitary adenylate cyclase activating peptide regulates neurally mediated airway responses

To clarify the protective effects of pituitary adenylate cyclase activating peptide (PACAP) on airway narrowing, we examined the effects of PACAP on smooth muscle contraction and plasma extravasation in guinea-pig airways. Smooth muscle contraction evoked by electrical field stimulation (EFS) or exogenously applied acetylcholine (ACh) or substance P (SP) was measured before and after PACAP in vitro. The effect of PACAP on airway plasma extravasation was also measured in vivo. In trachea, PACAP (10(-9) - 10(-7) M) significantly suppressed smooth muscle contraction evoked by EFS without affecting ACh sensitivity, suggesting that PACAP inhibits cholinergic neuroeffector transmission. In the main bronchi, PACAP (10(-9) - 10(-8) M) significantly suppressed the contraction evoked by EFS without affecting SP sensitivity in the presence of atropine, suggesting that PACAP inhibits SP release from excitatory nonadrenergic noncholinergic (eNANC) nerves. In animals treated with atropine and propranolol, PACAP attenuated the increase in plasma extravasation induced by electrical vagus stimulation or by SP. These results suggest that pituitary adenylate cyclase activating peptide may play a role in modulation of airway responses through inhibition of cholinergic and noncholinergic mechanisms.