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At least 1,351 records · Page 75Linked to original sources
PubMed1990

Serotonin induces constriction and relaxation of the guinea pig airway.

The response of guinea pig trachea to 5-hydroxytryptamine (serotonin; 5-HT) was investigated by studying tracheal strips suspended in organ chambers for isometric tension measurements. Serotonin concentrations of 0.1 to 10 microM produced concentration-dependent contractions, whereas at higher concentrations (10-300 microM) the agonist caused concentration-dependent relaxations. The 5-HT2 antagonist ketanserin shifted the bimodal 5-HT response-curve to the right (pA2 for ketanserin was 8.98). The 5-HT1A agonist, (+)-8-hydroxy-2-(di-N-propylamino)tetralin hydrobromide and 5-HT3 antagonist, ICS 205930 (3-tropanyl-indole-3-carboxylate) had no effect on the 5-HT-response curve. Incubation with atropine resulted in a depression of the maximal contractility and an increase in the EC50 without changing the bimodal nature of the concentration-response curve. Hexamethonium was able to block the atropine effect without significantly affecting the 5-HT concentration-response curve. Neither the constriction nor the relaxation was altered by propranolol, chlorpheniramine or capsaicin pretreatment. Histamine and carbachol preconstricted airways were also relaxed by 5-HT in a concentration-dependent fashion and this relaxation was antagonized by ketanserin (pKb for ketanserin in histamine preconstricted airways was 9.4). Epithelial denudation did not inhibit the 5-HT-induced relaxation. 5-HT stimulated inositol-monophosphate production which also exhibited a bimodal response and correlated well with the functional response. The above findings suggest that 5-HT causes both constriction and relaxation of the guinea pig airway, and that both responses are antagonized by a 5-HT2 receptor blocker. In addition, part of the constrictor response of 5-HT is mediated through a cholinergic preganglionic pathway. Finally, inositol-monophosphate production induced by 5-HT correlates with the functional response.

Acetylcholine↗
PubMedDate not supplied

Platelet-activating factor-induced coronary constriction in the isolated perfused guinea pig heart and antagonistic effects of the PAF antagonist WEB 2086.

Platelet-activating factor (PAF) has been called an important mediator of cardiovascular shock due to immunological reactions including anaphylaxis and endotoxic reactions. According to previous reports, PAF dose-dependently decreases ventricular contractility and coronary flow rates. Diverse mechanisms of the PAF-induced cardiodepressive effects have been postulated. Besides direct receptor stimulation, the release of other vasoactive mediators such as the eicosanoids has been reported. In this study, an attempt was made to characterize the direct PAF effects on the coronary circulation of the isolated constant pressure perfused guinea pig heart. A further objective was to evaluate whether PAF releases the potent vasoconstrictor thromboxane A2 in biologically relevant amounts. A continuous intracoronary infusion of the selective PAF antagonist WEB 2086 (3.7 x 10(-9) mol/min and 1.1 x 10(-7) mol/min, related to coronary flow rates of 1 ml/min) induced a dose-dependent vasodilation resulting in final perfusate concentrations of 2.5 x 10(-6) mol/l and 5.5 x 10(-5) mol/l, respectively. An intracoronary bolus injection of PAF in a submaximal dose (2.3 x 10(-10) mol, related to coronary flow rates of 1 ml/min) markedly decreased coronary flow rates and produced a significant increase in immunoreactive thromboxane B2 levels in the coronary effluent. WEB 2086 antagonized the PAF-induced coronary constriction in a dose-dependent manner. In addition, thromboxane release ceased entirely. In contrast, the selective thromboxane A2 receptor antagonist BM 13505 (0.9 x 10(-4) mol/1) attenuated the initial phase of coronary constriction only moderately. It is therefore concluded that the detected thromboxane release plays a subordinate role in the PAF-mediated coronary effects.

Animals↗
PubMed1990

[Sulfur dioxide-induced bronchial constriction in asthmatics and its prophylaxis by salbutamol].

Patients with bronchial asthma often develop acute attack in kitchen while burning honeycomb briquet which is widely used for cooking in southern China. Burning of a honeycomb briquet produces 0.6-4.3 ppm sulphur dioxide (SO2) in the kitchen air. To assess whether the above concentration of SO2 can induce bronchial constriction, we performed SO2 bronchial provocation test on 21 asthmatics (male 11, female 10, average age 28.8 +/- 2.0 years), 10 patients with allergic rhinitis (male 3, female 7.28 +/- 1.6 years) and 20 healthy non-smokers (male 13, female 7, 28.1 +/- 1.5 years). FEV1 showed no significant change in both healthy and rhinitis group even a maximal amount of SO2 (10 ppm) was given. The calculated PC20 FEV1 and PC35 SGaW in asthmatics were 3.7 +/- 0.22 ppm and 2.5 +/- 0.18 ppm respectively, which fell into the SO2 range yielded by a burning honeycomb briquet. Orally administered slow release salbutamol created protective effect in 5 out of 8 patients. Salbutamol inhalation, however, completely blocked SO2 induced bronchial constriction. We suggest that patient with bronchial asthma should receive salbutamol aerosol inhalation before cooking with burning honeycomb briquet.

Administration, Inhalation↗
PubMed1990

[An experimental study on the pathogenesis of congenital hand malformation--with reference to local disturbance in the limb bud and congenital constriction band syndrome].

In order to study congenital constriction band syndrome, we performed local cauterization of the lower limb buds of embryos in fertilized white leghorn eggs between hour 0 on day 4 (day 4-0) and day 7-0 of incubation. Constriction bands, acrosyndactyly, and amputation of digits, malformations characteristic of this syndrome, were all induced by intervention after day 5-0, when digital ray formation was first observed, indicating that they all develop after ray formation. Histological examination showed that encapsulation and shedding of the lesion containing hematoma and necrotic tissue at the distal end of a digital ray led to digit amputation. When the cells encapsulating this lesion extend over another digital ray, moreover, the ray tips fuse, while the rest of the two digits involved remain discrete-resulting in acrosyndactyly.

Animals↗
PubMed1989

Reversal of A23187-induced airway constriction in the guinea pig.

Conscious guinea pigs that were briefly exposed to an aerosol of A23187 developed a prolonged airway constrictive response that lasted at least 60 min. Cumulative i.v. doses of various drugs were given and reversal of dynamic compliance (Cdyn) examined. After the final dose of each agent, the animals were killed and excised lung gas volumes, i.e., pulmonary gas trapping, measured. Salbutamol, a beta-2 adrenoceptor agonist; phenidone, a 5-lipoxygenase inhibitor; aminophylline, a methylxanthine bronchodilator; dazoxiben, a thromboxane synthetase inhibitor; REV-6866, a 5-lipoxygenase inhibitor; LY53857, a 5-hydroxytryptamine receptor antagonist; and LY183001, a leukotriene D4/E4 antagonist, partially reversed Cdyn and reduced excised lung gas volume. Atropine, a cholinergic/muscarinic antagonist indomethacin, a cyclooxygenase inhibitor; pyrilamine, a histamine receptor antagonist; and SRI 63-072, a platelet activating factor antagonist, had little or no effect. For all animals, final Cdyn values were highly correlated with reduction of pulmonary gas trapping (r = -0.86, P less than .0001). We conclude that smooth muscle contraction is important in A23187-induced airway obstruction; 5-hydroxytryptamine, thromboxane A2 and lipoxygenase products may be involved in maintaining this response; and that this approach is useful for investigating reversal of ongoing airway constriction.

Airway Obstruction↗
PubMed1985

Effect of atrial natriuretic factor on renin secretion, plasma renin and aldosterone in dogs with acute unilateral renal artery constriction.

Atrial natriuretic factor (ANF) decreases renin secretion rate (RSR), plasma renin activity (PRA) and plasma aldosterone (PA) in normal dogs. To clarify further the mechanisms responsible for these effects, the left renal artery was constricted in seven anaesthetized dogs prior to ANF administration. Constriction of the left renal artery decreased (P < 0.05) ipsilateral mean renal perfusion pressure (MRPP, 29 +/- 7%), renal plasma flow (RPF, 42 +/- 11%) and glomerular filtration rate (GFR) and filtered sodium load (FLNa, 21 +/- 8.8%). Ipsilateral RSR and peripheral PRA tended to increase, although not significantly. Atrial natriuretic factor infusion did not alter GFR in the clamped kidney and failed to decrease RSR or PRA. Despite this, PA levels decreased significantly (7.8 +/- 2.4 to 5.6 +/- 1.8 ng%). These results suggest that ANF-induced inhibition of renin secretion is largely consequent on its renal haemodynamic actions and that suppression of aldosterone by ANF in vivo is due, in part, to direct effects on the adrenal cortex.

Aldosterone↗
PubMed1986

Cerebral arterial constriction due to contrast media.

Angiography, either with Iohexol or Hexabrix, was carried out on a series of baboons, each of which had both contrast media, but on separate occasions. A double blind trial showed that in the carotid and middle cerebral arteries: Hexabrix generally caused vasoconstriction by 1.5 min, but in spite of a subsequent injection at 6 min constriction had largely disappeared by 20 minutes. Iohexol was generally followed by less severe constriction, but it may persist for longer and even show an increase at 20 min.

Angiography↗
PubMed1985

[Clinical and roentgenological study of the hands in synbrachydactyly, constriction band syndrome and cleft hand complex].

One hundred and six cases of synbrachydactyly, 63 cases of constriction band syndrome and 69 cases of cleft hand complex were clinically and roentgenologically studied and the following results were obtained. Synbrachydactyly is a group of hand anomalies in which the bone reduction appears transversely, and its severest form is a hand missing all the hand bones and the distal portion of the forearm, and with rudimentary digits on the stump. The association of dermal syndactyly or pectoralis muscle defect frequently seen in the milder cases of synbrachydactyly would be a secondary change to mesodermal hypoplasia or a related, but isolated malformation. Cleft hand complex which includes ordinary cleft hand, central ray polydactyly and central ray osseous syndactyly is a group of hand anomalies basically due to an ectodermal abnormality of separation of the digits. However, it is frequently associated with mesodermal hypoplasia or defect of various severity. The hand malformation in constriction band syndrome has a definite characteristic that the area of bone reduction is limited in phalanges.

Female↗
PubMed1985

Nephrogenous cyclic AMP during extracellular volume expansion: relationship to early and late aortic constriction.

Prior data showed that both volume expansion (ECVE) and renal vasodilatation are associated with natriuresis and increased nephrogenous cAMP (NcAMP). Studies were done to examine the effect of ECVE on sodium excretion and NcAMP during early or late reduction in renal perfusion pressure (RPP) in an effort to define the role of renal vasodilatation on NcAMP during ECVE. In 8 thyroparathyroidectomized (TPTX) dogs, RPP to the left kidney was reduced (130 +/- 1.7 to 69 +/- 4 mm Hg), ECVE was then produced and finally RPP was allowed to rise to 126 +/- 2.2 mm Hg (group I). In 8 TPTX, ECVE was produced and then followed by a reduction in RPP (121 +/- 5 to 69 +/- 5 mm Hg; group II). cAMP was measured in aorta, renal veins and urine. In group I, renal plasma flow (RPF), fractional excretion of Na filtered (FeNa), urinary NcAMP (UNcAMP) and renal vein NcAMP (RVNcAMP) did not change in the constricted kidney while these parameters increased in the other kidney. After release of the constriction RPF (122 +/- 24 to 157 +/- 26 ml/min), FeNa (0.5 +/- 0.1 to 5 +/- 1.2%), UNcAMP (204 +/- 121 to 785 +/- 198 pmol/min, p less than 0.05) and RVNcAMP (277 +/- 213 to 1,565 +/- 403 pmol/min, p less than 0.02) rose significantly. In group II, FeNa, UNcAMP and RVNcAMP increased during ECVE and remained significantly elevated during the reduction in RPP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Congenital annular constricting bands: review of the literature and a case report.

Conditions associated with congenital annular constricting bands include autoamputation, acrosyndactyly of the hands and toes, clubfeet, lymphedema, pseud-arthrosis, and nail deformities. The association of congenital annular constricting bands and angular deformities of long bones is exceedingly rare. Reported is one such case treated with fibrous release and crescentic osteotomy.

Amniotic Band Syndrome↗
PubMed1985

Evidence for constriction of canine prenodal lymphatic vessels by vasoactive agents and carotid occlusion.

We measured pressure in a prenodal lymphatic in the canine forelimb during constant flow pump-perfusion of the brachial artery. We made bolus i.a. injections of 1.0 micrograms angiotensin II, norepinephrine, bombesin, or bradykinin, 20 micrograms 5-hydroxytryptamine (5HT), or occluded the carotid arteries. Norepinephrine, 5HT, or carotid occlusion produced regular rises in forelimb perfusion pressure and in lymphatic pressure. Angiotensin II increased forelimb arterial pressures but increased lymphatic pressure in only four experiments. Bombesin increased artery pressures but did not affect lymphatic pressure. Small vein pressure was increased by carotid occlusion, 5HT and norepinephrine. Increases in lymphatic pressure were coincident with increases in vein pressure but no related in magnitude. Bradykinin decreased forelimb arterial and venous pressures but did not affect lymphatic pressure. Either active constriction of lymphatic vessels or passive compression by movements of adjacent blood vessels could increase lymphatic pressure. These data do not preclude a passive component of pressure rise in the lymphatics nor do they support the concept. We conclude that active constriction of prenodal lymphatic vessels in the dog forelimb can occur in response to circulating vasoactive agents and bilateral carotid occlusion.

Angiotensin II↗
PubMed1985

Paradoxic pupillary constriction in a patient with congenital stationary night blindness.

Paradoxic pupillary constriction to an "off-step" of light was studied in a 35-year-old woman with congenital stationary night blindness. ERG was of the Schubert-Bornschein type (scotopic B-wave absent); fundi were normal for a high myope. Paradoxic constrictions were larger in response to full field and peripheral off-steps from low photopic levels than from higher photopic levels. The patient's "on response" was smaller in magnitude and slower in both latency and dynamics than the on-response of normal subjects. Pupillary hippus was larger in magnitude and more peaked in the patient than in normal subjects. Steady-state (tonic) pupil size increased paradoxically with increased light level over the range 1-2 log fL.

Adult↗
PubMed1979

Effect of a calcium antagonist on experimental constriction of human brain vessels.

In search for a potent dilatator or deactivator of constriction of cerebrovascular smooth muscle, the effects of a specific antagonist of the calcium influx necessary for the excitation-contraction coupling process was studied on isolated human pial arteries. The arteries were constricted by addition of noradrenaline, 5-hydroxytryptamine, human plasma or blood. All these agents induced a strong contraction which could effectively be reduced by addition of the Ca++-antagonist, nifedipine, to the organ bath. It is suggested that calcium antagonists might be of value in the treatment of cerebrovascular spasm following a subarachnoid hemorrhage.

Calcium↗
PubMed1982

Interaction between the renin-angiotensin and beta adrenergic nervous systems in drinking and pressor responses after renal artery constriction.

Constriction of the remaining renal artery of a uninephrectomized rat produced an increase in plasma renin level, a decrease in renal cortex renin level, an increase in blood pressure and a drinking response. Simultaneous infusion with the angiotensin II antagonist, saralasin, potentiated the rise in plasma renin level and blocked the rise in blood pressure. Drinking was only partially attenuated. Pretreatment with l-propranolol had no effect on the changes in plasma or kidney renin levels, but the increase in blood pressure was potentiated and the drinking response was attenuated. It is concluded that the pressor and drinking responses to renal artery constriction are partially mediated by the beta adrenergic nervous system.

Angiotensin II↗
PubMedDate not supplied

Cyclohexamide and renin release following renal artery constriction.

Renal artery constriction in the uninephrectomized conscious rat produced "renin release": i.e. an increase in plasma renin level and a decrease in renal cortex renin level, and an increase in mean arterial pressure. A high dose (4 mg.kg-1) of the protein synthesis inhibitor, cyclohexamide, halved the rise in plasma renin level (with no change in renal cortex renin level and a fall in mean arterial pressure). We suggest that the increase in plasma renin level following renal artery constriction depends on (a) release from preformed renin stores and (b) de novo renin synthesis.

Animals↗
PubMed1981

Adrenochrome-induced coronary artery constriction in the rat heart.

Adrenochrome, an oxidation product of epinephrine, has been demonstrated to produce cardiotoxic effects. In this study, we have investigated whether this agent can alter coronary resistance in isolated rat hearts. Concentrations of adrenochrome from 1 to 1000 ng/ml increased coronary pressure in a dose- and time-dependent manner. The highest concentration produced a 3-fold elevation in pressure after a 1-hr perfusion. Myocardial contractile force decreased only with either 100 or 1000 ng/ml of adrenochrome and this effect was evident after substantial elevations in coronary pressure. The elevation in coronary pressure was significantly reduced by two calcium antagonists, verapamil and D-600. Furthermore, the degree of constriction by adrenochrome was dependent on the CaCl2 concentration in the perfusion medium. High concentrations of indomethacin or propranolol attenuated the degree of coronary pressure elevation, whereas acetylsalicylic acid and phenoxybenzamine were without effect. Sulfinpyrazone, which has been shown to reduce the arrhythmogenic action of adrenochrome in vivo, significantly reduced the coronary pressure increases. These results suggest that adrenochrome is a potent coronary constricting agent in the rat heart and its action is seemingly dependent on external Ca++ availability.

Adrenochrome↗
PubMed1980

[Surgical treatment of congenital ring constriction: standard Z-plasty flaps versus microsurgical excision (author's transl)].

The author discusses the advantages and drawbacks of two procedures for surgical treatment of congenital ring constriction: the standard Z-plasty flaps and microsurgical excision. In the general opinion merely excising the tissues of the annular groove and suturing the skin borders together fails because the circular scar contracts, reproducing the constriction. In 6 infants, microsurgical excision of the annular groove, using a Zeiss operating microscope OPMI 7 and microsurgical instruments, with suturing of the skin borders proved to be a reliable technique giving excellent cosmetic results. Provided that all fibrous tissue is excised there is no risk of secondary contraction.

Extremities↗
PubMed1994

Effects of photodynamic therapy using mono-L-aspartyl chlorin e6 on vessel constriction, vessel leakage, and tumor response.

The effect of photodynamic therapy using mono-L-aspartyl chlorin e6 (NPe6) on both direct cytotoxicity and vascular damage was examined. Sprague-Dawley rats bearing chondrosarcoma tumor were given i.v. injections of 5 or 10 mg/kg NPe6 and exposed to 135-J/cm2 664-nm laser light either 4 or 24h after NPe6 injection. The percentage of viable tumor cells was estimated either immediately after the completion of light treatment or 24 h after treatment using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Measurements of arteriole constriction and venule leakage in normal cremaster tissues were made during and 1 h after the light treatment. Tumor response was evaluated for the 4 different NPe6 dose and time combinations. Both direct tumor cytotoxicity and vascular stasis were observed during light treatment. Vessel leakage did not occur. Blood flow stasis was a result of platelet aggregation and the mechanical obstruction of flow rather than vessel constriction. The magnitude of direct cytotoxicity and vascular response was dependent on both the amount of NPe6 delivered and the delay between injection and light treatment. Tumor cure was found in animals either when given high NPe6 doses or when treated early after NPe6 injection. Treatment regimens which maximized the effect of both vascular stasis and direct tumor cytotoxicity were found to produce the best tumor response. Dose combinations which produced vascular stasis with minimal early cytotoxicity did not result in cure. The combined mechanisms of damage after photodynamic therapy using NPe6 suggests that this photosensitizer may have specific advantages for clinical use and provides a benchmark for the development of new photosensitizers.

Animals↗