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PubMed1976

On the question of tachyphylaxis to isoproterenol in guinea pigs.

Isoproterenol (4 mug/kg, i.m.) decreased mortality of conscious guinea pigs to histamine, when histamine was injected 8 min after a single dose. But, when guinea pigs were injected with isoproterenol or saline every 20 min for 5 hr, followed by a histamine challenge 8 (or 120) min later, there was no difference in mortality between the two groups. This failure of repeated doses of isoproterenol to protect guinea pigs (from effects of histamine) may be related to its cardiovascular effects, since control blood pressure decreased significantly more in the isoproterenol group than in the saline group. This hypothesis was supported by the observation that histamine-induced mortality was significantly increased in guinea pigs treated with a vasodilator (minoxidil), whose blood pressure decreased to the same level (54 +/- 5 mm Hg) as that observed after repeated doses of isoproterenol. Tachyphylaxis to heart rate or blood pressure responses of isoproterenol was not observed. 10 repeated additions of isoproterenol to spontaneously beating atria or tracheal strips did not show any tachyphylaxis, nor did 15-20 additions of isoproterenol to perfused lungs.

Animals↗

PubMed1994

[Capsaicin-induced cough. Tachyphylaxis and the effect of anaesthesia on the pharynx].

We examined the reproducibility of capsaicin-induced cough thresholds and the influence of pharynx anaesthesia used to treat the cough. We performed cough threshold tests on ten patients with bronchial asthma and ten patients with chronic cough. The lowest level of capsaicin-induced cough threshold was defined as ten coughs. Tachyphylaxis in cough thresholds was examined three times at intervals of 30 minutes and 120 minutes after the initial test. We measured cough thresholds before and after pharynx anaesthesia with xylocainbiscus. There was no change in cough thresholds among the three times; nor was them any change in the thresholds before and after pharynx anaesthesia. But in five patients with acute pharyngitis, the cough thresholds after pharynx anaesthesia were greater than before. It was suggested that cough threshold tests had reproducibility 30 minutes and 120 minutes after indicating that tachyphylaxis did not exist. Furthermore it was suggested that pharynx anaesthesia influenced the cough threshold in patients with acute inflammation of the pharynx, but anesthesia had no influence on cough thresholds in patients without acute inflammation of the pharynx.

Adult↗

PubMed1986

A reinterpretation of tyramine sympathomimetic effect and tachyphylaxis.

In this commentary, the indirect sympathomimetic effect of tyramine and the phenomenon of tyramine tachyphylaxis are reinterpreted in terms of carrier-mediated exchange processes. Extracellular tyramine would exchange with intraterminal noradrenaline and, upon repeated tyramine administration, with a mixture of noradrenaline and tyramine progressively more enriched in the pharmacologically inactive amine.

Adrenergic Fibers↗

PubMed1984

In vivo allergen tachyphylaxis in guinea pig lung is mediated by endogenous prostaglandin E biosynthesis.

The term "allergen tachyphylaxis" (AT) describes a progressively decreased bronchial reactivity to allergen exposition after repeated allergen challenge [in our test system measured by sequential inhalative antigen challenge of sensitized guinea pigs (GP)]. The hypothesis that AT is mediated by endogenous prostaglandin E (PGE) biosynthesis was tested in vivo on GP sensitized to ovalbumin (OA). Different groups of animals were challenged with simultaneous inhalation of OA (repeatedly at time 0, 10, 20, 60 and 70 min) together with inhibitors of PGE-biosynthesis ( parachloromercurobenzoic acid = PCMB, copper sulfate = Cu, copper dithiotreitol complex = CuDTT , dithiotreitol = DTT and dimercaptopropanol = DMP) or agents increasing PGE production (aurothioglucose = Au, zinc dithiotreitol complex = ZnDTT and reduced glutathion = GSH). Bronchial obstruction was measured by whole body plethysmography . PCMB, Cu, CuDTT , DTT and DMP inhibited AT, whereas Au and ZnDTT enhanced AT. Acetylsalicylic acid (ASA) treatment prevented AT. Aerosols of PGE2, but not of prostacyclin or prostaglandin D2 restored AT in ASA treated animals. In addition to these in vivo experiments in vitro investigations showed that PCMB, Cu and DTT decreased while ZnDTT increased PGE biosynthesis of allergen challenged GP lungs. It is concluded that AT, an important self-protecting mechanism of GP bronchial asthma, is mediated at least in part via endogenous PGE.

Allergens↗

PubMed1976

[Reflexphotometric determinations of vasoconstriction after topical application of steroids. V. Vasoconstriction phaenomenon and tachyphylaxis after repeated steroid application (author's transl)].

On the basis of reflexphotometrical vasoconstriction tests it is demonstrated, that the intensity of vasoreactions caused by a first topical application of steroids, diminishes rapidly after repeated applications, until there is no response of vessels to a new application. This phaenomenon is know as tachyphylaxis and has been found in all tested glucocorticoids.

Administration, Topical↗

PubMed1987

Tachyphylaxis of juxtaglomerular epithelioid cells to angiotensin II. Differences between the electrical membrane response and renin secretion.

A study has been made of desensitization of the depolarizing response to angiotensin II of juxtaglomerular epithelioid and vascular smooth muscle cells in the mouse kidney afferent arteriole, of media cells from the mesenteric artery as well as of cultured smooth muscle and mesangial cells. In all cell types, desensitization to this effect of angiotensin II was observed. There was no cross-desensitization between angiotensin II and other depolarizing agonists. Hence, it is concluded that this desensitization is specific, i.e. of the tachyphylaxis type. Substances interfering with receptor recycling, such as chloroquine and monensin, did not block the recovery of the cells from desensitization after removal of the octapeptide. Desensitization to the action of angiotensin II was also observed with respect to its vasoconstrictor effect in the isolated perfused rat kidney. In contrast there was no desensitization of renin secretion in the isolated perfused rat kidney, nor in isolated hydronephrotic mouse tissue, nor in microdissected rat glomeruli.

Angiotensin II↗

PubMed2004

Rolipram reduces the inotropic tachyphylaxis of glucagon in rat ventricular myocardium.

Glucagon increases cardiac contractility through G(s) protein-coupled glucagon receptors, but the inotropic responses fade. The fade could be due to receptor desensitisation or to the action of phosphodiesterases (PDE), or to both mechanisms. We investigated the effects of the PDE4 inhibitor rolipram (1 microM) on the inotropic and cAMP-responses to glucagon in paced right ventricular strips of the rat heart. Responses to the partial agonist dobutamine, mediated through beta(1)-adrenoceptors, were studied for comparison. Glucagon increased contractility (-logEC(50)M=7.3 for maximum responses with E(max)=32% of the response to 9 mM Ca(2+)), but the responses tended to fade (-logEC(50)M=7.1 for faded responses with E(max)=11.5%). Dobutamine (-logEC(50)M=5.8, E(max)=56%) produced positive inotropic effects that did not fade. Rolipram did not affect basal contractility and cAMP levels. Rolipram enhanced the contractile responses to glucagon and reduced fade (-logEC(50)M=7.5 and 7.3 with E(max)=74% and 45% for maximum and faded responses respectively). The response to glucagon (0.1 microM) completely faded in the absence of rolipram, but only partially faded and then remained stable in the presence of rolipram (1 microM). Rolipram enhanced contractile responses to dobutamine (-logEC(50)M=6.0, E(max)=75%). Dobutamine (3 microM), but not glucagon (0.1 microM), increased tissue levels of cAMP. Consistent with the inotropic data, rolipram caused glucagon to augment cAMP and enhanced the effects of dobutamine. Thus, PDE4 activity limits the responses mediated through both glucagon receptors and beta(1)-adrenoceptors. PDE4-catalysed hydrolysis of cAMP contributes to the inotropic tachyphylaxis of glucagon.

Animals↗

PubMed1980

Stimulus summation and tachyphylaxis in estrogen response in sheep.

The response of the uterine circulation to estrogen has been extensively studied. Estrogen is the most potent vasodilator of the uterine bed. The magnitude of the vascular response depends on both the dose of estrogen used and the duration of exposure to estrogen. In this study, the relationship between the arterial concentration of estrogen, the duration and pattern of exposure, and the response was studied. This is a complex relationship, but one that is consistent with accepted models of estrogen-target tissue interaction. It was also shown that prolonged, high-concentration exposure results in tachyphylaxis.

Animals↗

PubMed1992

Homologous tachyphylaxis to bradykinin and its interference with allergic pleurisy in actively sensitized rats.

After recovery from a first intraplantar or intrathoracic stimulation with bradykinin, repeated daily provocation with this peptide resulted in a progressive loss of its ability to cause paw or pleural oedema, reaching 0-20% of the control within seven and four consecutive provocations, respectively. The phenomenon was shown to be time reversible, since the unresponsiveness ceased when stimulations were discontinued, and localized, since paw oedema evoked by the peptide was not modified after desensitization of either the contralateral paw or the pleural cavity. Furthermore desensitization to bradykinin did not influence the pleurisy elicited by either histamine (200 micrograms/cavity), 5-hydroxytryptamine (5-HT) (100 microgram/cavity) or platelet-activating factor (PAF) (1 microgram/cavity), suggesting that the desensitization was selective. In contrast, when actively sensitized animals were submitted to bradykinin-induced tachyphylaxis, pleural exudation and leukocyte influx induced by antigen were drastically reduced, strongly implying bradykinin in this process. We demonstrated that repeated daily stimulation with bradykinin cause selective, local and reversible auto-refractoriness, which may be useful as a tool in attempting to evaluate the role of this peptide in inflammation.

Amino Acid Sequence↗

PubMed1996

Elevation in arterial blood pressure following the development of tachyphylaxis to peroxynitrite.

The systemic administration of peroxynitrite produces transient reductions in mean arterial pressure and vascular resistances in anesthetized rats. The repeated administration of peroxynitrite results in tachyphylaxis. We now report that anesthetized rats (n = 8) treated with peroxynitrite (10 injections of 10 mumol/kg i.v.) subsequently develop increases in mean arterial pressure (20 +/- 4%) and hindquarter (153 +/- 28%), renal (93 +/- 21%), and mesenteric (133 +/- 25%) vascular resistances. These findings suggest that the in vivo production of peroxynitrite may contribute to the pathogenesis of hypertension.

Animals↗

PubMed1980

Tachyphylaxis to inhaled isoproterenol and the effect of methylprednisolone in dogs.

Acute tachyphylaxis can be induced to inhaled isoproterenol (ISO) in anesthetized, closed-chested mongrel dogs. The responsiveness to ISO measured as the percent reduction in methacholine-induced bronchoconstriction was decreased significantly (p less than 0.01) after a 1-hr period of repeated ISO inhalations (ISO-loading). Intravenous administration of methylprednisolone (1 mg/kg) reversed the decrease in responsiveness to ISO.

Animals↗

PubMed1984

Increased leukocyte sensitivity to phosphodiesterase inhibitors in atopic dermatitis: tachyphylaxis after theophylline therapy.

Previous studies have demonstrated elevated cyclic 3',5'-adenosine monophosphate specific phosphodiesterase (PDE) activity in mononuclear leukocytes (MNL) from patients with atopic dermatitis (AD) and with allergic respiratory disease. We have studied the effect of PDE inhibitors on MNL from normal subjects and from patients with AD. We measured PDE activity in MNL after in vitro exposure to Ro20-1724, theophylline, and isobutylmethylxanthine. The effect of PDE inhibitors was also measured in MNL of patients during and after oral theophylline therapy. There was a dose-response effect of Ro20-1724 on PDE activity of AD cells. This activity was significantly more inhibited than that in MNL of normal subjects or in MNL of theophylline-treated patients with AD. The inhibition pattern of PDE in MNL of treated patients with AD did not vary significantly from the pattern observed in MNL from normal patients. Two weeks after oral theophylline was stopped, the PDE activity in MNL was once again susceptible to in vitro inhibition. The relative resistance of MNL to PDE activity in normal subjects to in vitro PDE inhibitors may be due to the existence of different PDE enzyme forms or the presence of endogenous inhibitors. The clinical importance of the tachyphylaxis observed is uncertain, but our results suggest that intermittent dosing with PDE inhibitors may provide a therapeutic advantage in treatment of AD and other atopic diseases.

Administration, Oral↗

PubMed1993

Studies on the mechanism of the contractile action of rat calcitonin gene-related peptide and of capsaicin on the guinea-pig ileum: effect of hCGRP (8-37) and CGRP tachyphylaxis.

Both the neuropeptide calcitonin gene-related peptide (CGRP) and the sensory stimulant drug capsaicin exert excitatory as well as inhibitory actions in the guinea-pig ileum. It has been known that their excitatory effects are due to activation of myenteric neurons. In the present study it has been established that a fairly high concentration (3 microM) of the CGRP antagonist human alpha CGRP (8-37) [hCGRP (8-37)], which has been known to reverse the inhibitory effects of rCGRP, failed to inhibit longitudinal contractions of ileal longitudinal muscle-myenteric plexus strips due to rat (r) CGRP. Instead, a slight enhancement of the contractions was observed, probably due to the inhibition of the relaxant effect. Tachyphylaxis to rCGRP was able to markedly reduce the contractile action of rCGRP but did not influence contractions due to capsaicin (1 microM). It is concluded that myenteric neuronal excitation due to rCGRP involves receptors not sensitive to hCGRP (8-37). Moreover, neuronal excitation by capsaicin does not seem to involve a CGRP-like mediator.

Acetylcholine↗

PubMed1982

Multiple subcutaneous injections of somatostatin induce tachyphylaxis of the suppression of plasma insulin, but not glucagon, in the rat.

The time course of pancreatic effects of somatostatin was studied over a period of 2 h in unanesthetized unrestrained rats after administration of the peptide by intravenous infusion and by single and multiple subcutaneous injections. During infusion of 10 and 30 micrograms/kg per min, somatostatin continuously suppressed plasma insulin and plasma glucagon. Plasma glucose was significantly increased at the lower dose, but not affected at the higher dose. Single subcutaneous injections of 0.3 and 3 mg/kg decreased plasma insulin and glucagon dose-dependently for 20-60 min without affecting plasma glucose. Multiple subcutaneous injections of somatostatin (one to four doses of 3 mg/kg, administered at intervals of 30 min) caused an initial decrease of plasma insulin (at 30 min), a rebound-increase at 60 and 90 min, and a final return to control values by 120 min. Plasma glucagon remained continuously suppressed. Plasma glucose increased significantly at 60 and 90 min and tended to return towards control values thereafter. In conclusion, pancreatic B cells - but not A cells - of the rat develop tachyphylaxis to somatostatin within 2 h after multiple subcutaneous injections of the peptide. By this mode of administration, 'selective' suppression of plasma glucagon can be achieved with somatostatin in the rat.

Animals↗

PubMed1994

Repeated intradermal injection of low-dose carrageenan induces tachyphylaxis to evoked hyperalgesia.

Changes in the thresholds to noxious mechanical and thermal stimulation were monitored in a group of normal sheep at different times (30 min-24 h) following intradermal injection of either low-dose (0.0625%) carrageenan, a widely used mucopolysaccharide irritant, or saline (0.9%) into the lateral aspect of the fore limb. Thresholds to noxious mechanical stimulation were measured on the ipsilateral limb whereas thresholds to noxious thermal stimulation were measured at a site distant to that of the injection, the ipsilateral ear. During the first 2 h after carrageenan injection the thresholds to noxious thermal stimulation fell, while thresholds to noxious mechanical stimulation were unaltered. The evoked hyperalgesia was reversed by the administration of non-steroidal anti-inflammatory agents. Hyperalgesia was not present 4 h after carrageenan injection in control or treated animals. This experiment was carried out on 3 further occasions and a diminishing response to injection of carrageenan was observed, suggesting development of tachyphylaxis to evoked thermal hyperalgesia.

Animals↗

PubMed2005

Chronic sildenafil improves erectile function and endothelium-dependent cavernosal relaxations in rats: lack of tachyphylaxis.

OBJECTIVES: Sildenafil is a widely-prescribed effective on-demand treatment of erectile dysfunction (ED). Chronic treatment with sildenafil could help patients with ED. METHODS: The effects of an 8-week long treatment with sildenafil (60 mg/kg/d sc) in male Sprague Dawley rats were evaluated on electrically-elicited erectile responses in vivo before and after an acute injection of sildenafil (0.3mg/kg iv). In addition, endothelium-dependent and -independent relaxations of strips of corpus cavernosum in vitro were examined. All experiments were performed 36 hours after the last injection of sildenafil. RESULTS: Endothelium-dependent relaxations of cavernosal strips to acetylcholine were enhanced after chronic treatment with sildenafil while relaxations to A23187 or sodium nitroprusside were unchanged. Frequency-dependent erectile responses elicited by cavernous nerve stimulation were significantly improved. Moreover, the erectile responses to acute sildenafil were greater in chronically-treated rats with sildenafil. CONCLUSIONS: This is the first report providing experimental support for chronic dosing with sildenafil which could be of use for patients that are poor responders to on-demand treatment. Chronic sildenafil may regulate the transduction pathway leading to the activation of eNOS but has no effect on NO bioavailability or on the cGMP pathway, thereby eliminating a possible concern for tachyphylaxis.

Animals↗

PubMed1976

Dose-response effects of prostaglandin F2alpha on the rabbit oviduct: reproductive endocrine influence and tachyphylaxis.

The dose-response effect of PGF2alpha on the perfused oviduct of estrous and ovariectomized rabbits was determined. The oviducts of ovariectomized rabbits were more sensitive to the contractile effects of PGF2alpha than those of estrous rabbits. This was demonstrated by a significant difference in the slope of the dose-response curves and in the magnitude of the maximum responses between the two groups. Blood pressure responses (depressor) to PGF2alpha were not affected by the reproductive hormonal status of the rabbits. The oviduct (estrous rabbits) developed tachyphylaxis to the effect of PGF2alpha. It was concluded that the response of the rabbit oviduct to PGF2alpha is dependent on the reproductive hormone status of the animal and that the oviduct becomes insensitive to the effects of PGF2alpha with repeated administration.

Animals↗

PubMed1997

Tachyphylaxis of the B1 kinin receptor in porcine endotoxin shock.

Previous experiments in anesthetized pigs have demonstrated that blockade of the bradykinin B2 receptor in experimental endotoxin shock attenuates LPS-induced organ failure, lung dysfunction and mortality. Additional B1 receptor blockade in this situation seems to counteract the beneficial effects of B2 blockade. This suggests that the upregulation of B1 receptors during porcine LPS shock may be a useful mechanism of host defense. Furthermore, infusion of a B1 agonist during septic shock may be of therapeutic benefit. In order to prepare an experiment with B1 stimulation in LPS shock, we conducted a study in anesthetized pigs, in which the B1 receptor has been upregulated by infusion of bacterial lipopolysaccharide (LPS), by evaluating the effect of constant intravenous infusions of the B1 agonist des-Arg10-kallidin on the hypotensive response to bolus doses of this agonist. Following infusions of lipopolysaccharide from S. abortus equi, anesthetised pigs received repeated intra-arterial bolus injections of des-Arg10-kallidin before and during continuous infusions of this agonist in doses of 3, 10, 30 and 100 ng/kg/min. We found that all doses greater than 3 ng/kg/min produced attenuation of the hypotensive response produced by bolus administration of the B1 agonist des-Arg10-kallidin. We conclude that tachyphylaxis is an important feature to be considered in experiments with continuous administration of a B1 agonist in LPS shock.

Animals↗