No abstract available.
Animals ; Isoproterenol* ; Plasma* ; Rats* ; Renin*

No abstract available.
Amnion* ; Dinoprostone* ; Humans* ; Isoproterenol* ; Progesterone*

BACKGROUND: Oral beta-blocker is initially used to prevent the symptons in patients with vasovagal syncope or presyncope. But, beta-blocker treatment may actually cause worsening of symptoms in some patients. The purpose of the present study was to evaluate the efficacy of oral beta-blocker in preventing symptoms during repeat head-up tilt test in patients who had a positive response in initial head-up tilt test. METHOD: Patients. Among the 150 patients with unexplained syncope or presyncope who underwent head-up tilt from October 1994 to January 1996, forty-three patients, who were taking beta-blocker and underwent repeat head-up tilted test, were included in this study. Initial head-up tilt test. Each patients was tilted to the 70 degree upright position for 30 minutes. If the test was negative in the baseline tilt, intravenous isoproterenol was started at 1 (micro)g/min and then increased by 1 (micro)g/min every three minutes to al maximum of 5 (micro)g/min while maintaining 70 degree upright position. Repeat head-up tilt test. The test was repeated while each patients was taking atinolol. The repeat test was continued until reaching at the stage where each patient had a positive response in initial test. RESULTS: 1) In initial head-up tilt test, most (91%) of a positive response occured during isoproterenol provocation. 2) In repeat head-up tilt test on atenolol, thirty-four patients(79%) had a negative response. But nine patients(21%) still had a positive response. 3) Nonresponsive group showed younger age and shorter time period to a positive response in initial head-up tilt test than responsive group. CONCLUSION: It may be useful to assess the effectiveness of beta-blocker by repeat head-up tilt before deciding long term treatment, especially younger age group.
Adult* ; Atenolol ; Humans ; Isoproterenol ; Syncope* ; Syncope, Vasovagal*

No abstract available.
Animals ; Isoproterenol* ; Nitric Oxide* ; Rats* ; Urinary Bladder*

PURPOSE: To investigate the effect of beta-adrenergics on the production of nitric oxide (NO) in cultured trabecular meshwork cells. METHODS: Primarily cultured porcine trabecular meshwork cells were exposed to timolol and to propranolol at various concentrations. Cellular survival was assessed by MTT assay and the production of nitrite was assessed by Griess reaction after 24 hours and 3 days respectively. Also investigated was the effect of co-administraton of timolol and isoproterenol. RESULTS: After exposure for 24 hours, neither drug affected the cellular survival. Timolol and propranolol inhibited the production of NO significantly (p<0.05). Isoproterenol abolished timolol-induced inhibition of NO production after 24 hours. These results were similar after exposure for 3 days. CONCLUSIONS: Both timolol and propranolol inhibit the production of NO in trabecular meshwork cells and isoproterenol abolished this effect. These results suggest that beta-adrenerics involves in the production of NO in trabecular meshwork cells.
Isoproterenol ; Nitric Oxide* ; Propranolol ; Timolol ; Trabecular Meshwork*

PURPOSE: This study was aimed at investigating the role of betaadrenoceptor subtypes in mediating the relaxation and contraction of seminal vesicles in rabbits. MATERIALS AND METHODS: Relaxation or contractile responses of epithelium- removed muscle strips of a rabbit seminal vesicle, which were precontracted with 10-5M norepinephrine, to selective betasubtypes-adrenoceptor agonists were observed in an organ bath. The contractile responses induced by isoproterenol were also observed after application of selective antagonists. RESULTS: Isoproterenol showed a concentration-dependent contractile response, but the contractility was weaker than those with phenylephrine and norepinephrine. The betaselective-agonists(xamoterol for beta, clenbuterol for beta and BRL37344 for beta) alone evoked neither contraction nor relaxation. However, the beta- and beta-agonists inhibited the contraction of the precontracted strips with 10-5M norepinephrine, while the beta-agonist enhanced the contraction. The pretreatment with a beta-antagonist(ICI118551) reduced the tension of the strips developed by 10-4M isoproterenol, but the beta-(atenolol) and beta-(SR59230A) antagonists showed no changes in the response. CONCLUSIONS: beta- and beta-adrenoceptors seem to mediate the relaxation of the seminal vesicle, while the beta-adrenoceptor may have a supplementary role in contraction.
Baths ; Clenbuterol ; Isoproterenol ; Negotiating ; Norepinephrine ; Phenylephrine ; Rabbits ; Relaxation* ; Seminal Vesicles*

To identify the role of the myocardial beta-adrenergic pathway in congestive heart failure, we examined beta-adrenergic receptor density and C-AMP by receptor assay with mononuclrear cell and polymorphonuclear cell in 7 cases of normal control and 7 cases of congestive heart failure. The results were as follows: 1)The mean serum concerntrations of norepinephrine(566.00+/-48.12 pg/ml)and epinephrine(353.14+/-44.24 pg/ml) in congestive heart failure group were significantly higher than those(218.12+/-17.08 pg/ml, 187.23+/-24.62 pg/ml)in normal contral group(P<0.05 for each comparison). 2) In normal control group, the receptor concentration of mononuclear cell was 35.51+/-19.19 fmol/mg and that of polymorphonuclrear cell was 35.53+/-15.05 fmol/mg. The affinity constant of mononuclear cell was(2.47+/-0.42)x10(9)/m and that of polymorphonuclear cell was(2.24+/-0.58)x10(9)/m. 3) In congestive heart failure group, the receptor concentration of mononuclear cell(29.31+/-5.41 fmol/mg) was significantly lower than that in normal control group(p<0.05). And the affinity constant(3.57+/-1.02)x10(9)/m) was significantly higher than that in normal control group(p<0.05). 4) In congestive heart failue group, the receptor concentration of polymorphonuclear cell(33.15+/-10.46 fmol/mg) was not significantly different from that in normal control group. And the affinity constant(2.66+/-0.43)x109/m) was not significantly different from that in normal control group. 5) In congestive heart failure group, the C-AMP concentrations of mononuclear cell(basal 119.9+/-17.2 pmol/min/mg, isoproterenol stimulation 137.2+/-23.2 pmol/min/mg) were significantly lower than those(basal 205.2+/-21.1 pmol/min/mg, isoproterenol stimulation 267.5+/-34.3 pmol/min/mg) in normal control group(p<0.05 for each comparison). 6) In congestive heart failure group, the C-AMP concentrations of polymorphonuclear cell(basal 115.2+/-34.3 pmol/min/mg, isoproterenol stimulation 142.5+/-20.5 pmol/min/mg) were significantly lower thatn those(basal 186.3+/-24.2 pmol/min/mg, isoproterenol stimulation 233.4+/-32.2 pmol/min/mg) in normal control group(P<0.05 for each comparison). In conclusion, a decrease in beta-adrenergic density in congestive heart failure leads to subsensitivity of the beta-adrenergic pathway and decreased beta-agonist-stimulated contraction. However, other factors may be important in adenylate cyclase activation, and so further research is needed.
Adenylyl Cyclases ; Estrogens, Conjugated (USP)* ; Heart ; Heart Failure* ; Isoproterenol ; Plasma*

OBJECTIVES: Recently, irritable bowel syndrome (IBS) is known to be related with neurotransmitters. This study was designed to determine beta-adrenergic receptor function in patients with IBS and to compared with normal controls to examine the relationship between beta-adrenergic receptor function and anxiety in IBS patients. METHODS: Eighteen IBS patients were compared with the same number of age and sex-matched normal subjects in terms of beta-adrenergic receptor function and psychological variables reflecting anxiety levels. To assess beta-adrenergic receptor function, Chronotropic 25 dose (CD25) was calculated via isoproterenol stimulation test. RESULTS: CD25 values in the patient group were significantly lower than those in the control group, which reflected increased beta-adrenergic receptor function (2.19+/-1.08 versus 3.89+/-1.64, p<0.05). Patients with IBS showed higher HAM-A scores (8.88+/-4.88 versus 3.59+/-2.65, p<0.01), HAM-D scores (6.41+/-4.02 versus 2.47+/-2.40, p<0.01), BDI scores (9.00+/-6.21 versus 4.72+/-4.30, p<0.05), and STAI scores (STAI-S: 43.41+/-6.34 versus 33.83+/-8.18, p<0.01, STAI-T: 44.65+/-7.43 versus 38.17+/-8.45, p<0.05). In addition, HAM-A scores were negatively correlated with CD25 values in the patient group (r=-0.424, p<0.01). CONCLUSION: These results suggest that beta-adrenergic receptor function is increased in patients with IBS, which could affect increased anxiety levels in these patients.
Anxiety* ; Humans ; Irritable Bowel Syndrome* ; Isoproterenol ; Neurotransmitter Agents

The chromatic activity and potency of various sympathomimetic amines were examined in the normal frogs using the Hogben and Slome Index as a simple method for measuring melanophore responses. All the sympathomimetic amines tested in this experiment exhibited the marked aggregation of melanophores. Among these amines, the order of potency in producing the melanophoreaggregation was catecholethylamine derivatives (epinephrine and isoproterenol) monohydroxyphenylethylamine derivative (tyramine) with exception of phenylephrine>nonhydroxyphenyletyhlamine derivatives (ephedrine and propadrine). Of catecholethylamine derivatives, thc melanophore-aggregating activity of epinephrine was more potent than that of isoproterenol. On the other hand, phenylephrine belong to the monohydroxyphenylethylamine derivatives was the least potent agent than the other amines tested.
Amines ; Dronabinol ; Epinephrine ; Hand ; Isoproterenol ; Melanophores* ; Phenylephrine ; Skin* ; Sympathomimetics*

Syncopes are the most common non-epileptic attacks mimicking epileptic seizures. Among them, cardiogenic syncope is potentially life threatening. A 49 year old man was refered for the recurrent episodes of loss of consciousness with tonic posture and upward eyes deviation. The electrocardiogram showed polymorphologic ventricular tachycardia during attacks, which normalized after that. He was treated with isoproterenol and symptoms subsided. Here, we report a case of ventricular tachycardia manifested as epileptic seizures.
Electrocardiography ; Epilepsy* ; Isoproterenol ; Posture ; Seizures ; Syncope ; Tachycardia, Ventricular* ; Unconsciousness