BACKGROUND: Uracil nucleotides are stored in platelets and all other cells, and are released into the extracellular space upon stimulation. They show various biological responses but their actions and mechanism are not well understood. This study was conducted to investigate the effects of uridine 5'-triphosphate(UTP) on vascular tone and to identify the characteristics of their receptors. METHODS: Aortic ring preparation were made from the rat descending thoracic aorta. Endo-thelial cells were preserved or removed by gentle rubbing, The basal tension of aortic ring was lgm and isometric contraction were recorded on polygraph using force transducer. RESULTS: In aortic ring Precontracted by 100nM norepinephrine, UTP induced dual effect with various concentrations. UTP elicited endothelium-dependent relaxation at low concentrations(100nM-10microM), and endothelium-independent contraction at high concentrations(more than 30microM). Among uracil nucleotides, UDP was as much effective as UTP in vascular tone, but UMP and uridine were not. UTP(pA50 6.15) was more potent than ATP(5.17), ITP(4.75) and other nucleotides(TTP, GTP, CTP). At basal tension, UTP induced relaxation at low concentrations and contraction at hige concentrations in endothelium-intact ring. But in endothelium-removed ring, UTP elicited only contraction. Prior treatment of aortic ring with suramin, a non-selective P2-purinoceptor blocker, inhibited UTP-Induced relaxation and contraction. Reactive blue-2, a P2gamma purinoceptor blocker, inhibited relaxation only, but alpha, beta-methylene ATP, a P2x Purinoceptor blocker, enhanced contractile response. ATP inhibited the UPT-induced relaxation, but 2-methylthio ATP did not alter the effects of UTP. It means that UTP and ATP act at the same receptor but 2-methylthio ATP does not. CONCLUSION: These results suggest that UTP-induced relaxation is mediated by nucleotide receptors on endothelium and the contraction is mediated by pyrimidinoceptors on vascular smooth muscle.
Adenosine Triphosphate ; Animals ; Aorta ; Aorta, Thoracic* ; Endothelium ; Extracellular Space ; Guanosine Triphosphate ; Isometric Contraction ; Muscle, Smooth, Vascular ; Norepinephrine ; Rats* ; Receptors, Purinergic ; Receptors, Purinergic P2X ; Relaxation ; Suramin ; Transducers ; Uracil Nucleotides ; Uridine Diphosphate ; Uridine Monophosphate ; Uridine Triphosphate ; Uridine*

BACKGROUND: Adenosine 5'-tetraphosphate(ATPP), an endogenous nucleotide, is stored in cells and released into the extracellular space upon stimulation. Some of the biological responses to ATPP were reported, but characteristics of its receptor were not well known. Present study was conducted to investigate the effects of ATPP on mechanical contractility, resting membrane potential and action potential of rat left atrium. METHODS: Left atrium was isolated from Sprague-Dawley rat. Mechanical contraction induced by electrical field stimulation(EFS) was recorded on polygraph using force transducer. With glass microelectrodes(10 MOmega), potential difference across the membrane was measured and recorded on an oscilloscope and a polygraph. RESULTS: ATPP reduced the left atrial contractility with concentration-dependent manner. ATPP also hyperpolarized the resting membrane potential and decreased the action potential duration of the left atrial cell. Nucleotides other than ATPP, such as ATP, ADP, AMP and adenosine, have the same effect as ATPP. However, there is no difference among the nucleotides. Prior treatment of DPCPX, a P1-purinoceptor blocker, inhibited the ATPP-induced negative inotropism and changes of the membrane potential. But suramin, a nonselective P2-purinoceptor blocker, did not alter the effects of ATPP. alpha, beta methylene ADP and adenosine deaminase, which attenuates hydrolysis of adenine nucleotides and inactivates adenosine respectively, did not influence the effects of adenine nucleotides except for adenosine. CONCLUSION: ATPP reduced the mechanical contractility, hyperpolarized the resting membrance potential and decreased duration of action potential of rat left atrium. These effects were induced by ATPP directly, not by adenosine from hydrolyzed ATPP.
Action Potentials ; Adenine Nucleotides ; Adenosine Deaminase ; Adenosine Diphosphate ; Adenosine Triphosphate ; Adenosine* ; Animals ; Extracellular Space ; Glass ; Heart Atria ; Hydrolysis ; Membrane Potentials ; Membranes ; Muscle Contraction ; Nucleotides ; Rats ; Rats, Sprague-Dawley ; Receptors, Purinergic ; Suramin ; Transducers

BACKGROUND: One of the most common side effects of antidepressant medication is orthostatic hypotension, which can be caused by impaired vasoconstriction. This study was designed to compare the inhibitory effects of antidepressants, including selective serotonin reuptake inhibitors (SSRIs), on the contractile responses to alpha1-adrenergic receptor activation and depolarization in isolated rat aorta. METHODS: Vascular rings were suspended for the measurement of isometric tension in a water-jacketed bath filled with Tyrode solution. After pretreatment with antidepressant for 20 min, vasoconstriction induced by norepinephrine (NE) or 35 mM K+ was measured and compared to the control response. RESULTS: Whereas trazodone and tricyclic antidepressants (TCAs) selectively inhibited NE-induced vasoconstriction, SSRIs inhibited depolarization-induced vasoconstriction more potently. The IC50 value of fluoxetine on depolarization- induced vasoconstriction was 3.29 microM, which is consistent with the previous results on L-type Ca2+ currents of cardiac myocyte. Moclobemide, a monoamine oxidase inhibitor, had no effect on vasoconstriction induced by either alpha- adrenergic receptor activation, or depolarization. CONCLUSION: These results suggest that SSRIs, different from TCAs and trazodone, have potent inhibitory actions to depolarization-induced contraction that may be due to blocking Ca2+ entry through L-type Ca2+ channel.
Animals ; Antidepressive Agents ; Antidepressive Agents, Tricyclic ; Aorta* ; Baths ; Fluoxetine ; Hypotension, Orthostatic ; Inhibitory Concentration 50 ; Moclobemide ; Monoamine Oxidase Inhibitors ; Myocytes, Cardiac ; Norepinephrine ; Rats* ; Receptors, Adrenergic ; Serotonin Uptake Inhibitors* ; Trazodone ; Vasoconstriction*

BACKGROUND: Extracellular ATP, released from platelets and nerve endings, plays significant roles in the regulation of circulation. The effects of ATP depend on the location of the vessels and the species of experimental animals. Until now, studies were limited to arteries, so we compared the effects of ATP in rat vena cava with those in the aorta and attempted to identify the characteristics of their receptors. METHODS: Vascular rings were isolated from the rat inferior vena cava and descending thoracic aorta. Endothelial cells were preserved or removed by gentle rubbing. The isometric contractions were recorded on polygraph using a force transducer. RESULTS: In the vena cava ring precontracted by 100 nM norepinephrine (NE), ATP elicited relaxations in a dose-dependent manner. These effects were abolished by removal of the endothelium or pretreatment with a nitric oxide synthase inhibitor. Relaxations to ATP in the vena cava (EC50 :9.9 microM) were less potent than those in the aorta (1.7 microM). The relative order of potencies was ADP>ATP>AMP>adenosine, but the maximal relaxation to ADP was smaller than to ATP. ATP-induced vasorelaxation was blocked by suramin, a nonselective antagonist for P2 purinoceptor and reactive blue-2, a P2Y blocker. At basal tension, ATP contracted the vena cava dose-dependently and these effects were potentiated by endothelium-removal. Contractions in the vena cava were also less potent than in the aorta, and the order of potencies was alpha, beta-MeATP>UTP>ATP>ADP>AMP=adenosine. ATP-induced vasoconstriction was blocked by suramin and alpha, beta-MeATP, a desensitizing antagonist of P2X purinoceptor, and potentiated by pretreatment with UTP. CONCLUSION: These results suggest that ADP and ATP acts on P2Y1- and P2Y2-purinoceptor in the endothelium, respectively and induces vasorelaxation of the vena cava, which is mediated by nitric oxide. Since ATP and UTP induced vasoconstriction in endothelium-denuded condition, it may be mediated by the activation of the P2X and P2Y4, 6 purinoceptor on smooth muscles, respectively.
Adenosine Diphosphate ; Adenosine Triphosphate ; Animals ; Aorta ; Aorta, Thoracic ; Arteries ; Endothelial Cells ; Endothelium ; Isometric Contraction ; Muscle, Smooth ; Nerve Endings ; Nitric Oxide ; Nitric Oxide Synthase ; Norepinephrine ; Rats* ; Receptors, Purinergic P2 ; Receptors, Purinergic P2X ; Receptors, Purinergic* ; Relaxation ; Suramin ; Transducers ; Uridine Triphosphate ; Vasoconstriction ; Vasodilation ; Vena Cava, Inferior*

Familial hemiplegic migraine(FHM) is an autosomal dominant subtype of migraine with aura, characterized by the occurrence of hemiplegia during the aura. Two subforms of FHM families exist; pure FHM in 80% and FHM families with cerebellar symptoms in 20%. Half of the known FHM families show genetic linkage to chromosome 19p13, and in these families FHM is caused by missense mutations in a neuronal P/Q type calcium channel alpha-1 subunit gene(CACNA1A gene). Linkages to 1q31 and 1q21-23 have also been established. Other families are linked neither to chromosome 19 nor 1. Clinical variabilities are partially associated with the various types of CACNA1A gene mutations. FHM is distinguished from more frequent migraine types by a clear, dominant inheritance pattern and the relative absense of other headache types. Further investigation of FHM will help to clarify the genetics of more common migraine. We describe a male patient with FHM with a brief review of the literature.
Calcium Channels ; Chromosomes, Human, Pair 19 ; Epilepsy ; Genetic Linkage ; Genetics ; Headache ; Hemiplegia ; Humans ; Inheritance Patterns ; Male ; Migraine Disorders ; Migraine with Aura* ; Migraine without Aura ; Mutation, Missense ; Neurons

No abstract available.
Cell Line* ; Humans* ; Interferon-gamma* ; Matrix Metalloproteinases* ; Tumor Necrosis Factor-alpha* ; Urinary Bladder Neoplasms* ; Urinary Bladder*

No abstract available.
Cell Line* ; Humans* ; Interferon-gamma* ; Matrix Metalloproteinases* ; Tumor Necrosis Factor-alpha* ; Urinary Bladder Neoplasms* ; Urinary Bladder*

Decreased cardiac contractility occurs in endotoxicosis, but little is known about the ionic mechanism responsible for myocardial dysfunction. In this study, we examined the changes in Ca2+ and K+ currents in cardiac myocytes from endotoxin-treated rat. Ventricular myocytes were isolated from normal and endotoxemic rats (ex vivo), that were treated for 10 hours with Salmonella enteritidis lipopolysaccharides (LPS; 1.5 mg/kg) intravenously. Normal cardiac myocytes were also incubated for 6 hours with 200 ng/ml LPS (in vitro). L-type Ca2+ current (ICa,L) and transient outward K+ current (Ito) were measured using whole cell patch clamp techniques. Peak ICa,L was reduced in endotoxemic myocytes (ex vivo; 6.00.4 pA/pF, P<0.01) compared to normal myocytes (control; 10.90.6 pA/pF). Exposure to endotoxin in vitro also attenuated ICa,L (8.40.4 pA/pF, P<0.01). The amplitude of Ito on depolarization to 60 mV was reduced in endotoxin treated myocytes (16.51.5 pA/pF, P<0.01, ex vivo; 20.00.9 pA/pF, P<0.01, in vitro) compared to normal myocytes (control; 24.71.0 pA/pF). There was no voltage shift in steady-state inactivation of ICa,L and Ito between groups. These results suggest that endotoxin reduces Ca2+ and K+ currents of rat cardiac myocytes, which may lead to cardiac dysfunction.
Animals ; Depression* ; Lipopolysaccharides ; Muscle Cells ; Myocytes, Cardiac* ; Patch-Clamp Techniques ; Rats* ; Salmonella enteritidis

OBJECTIVETo observe the early and late symptomatic, pathological and immunological changes in an intranasal ovalbumin-induced animal model of allergic rhinitis in guinea pigs.

METHODSGuinea pigs were intranasally sensitized with ovalbumin absorbed on aluminum hydroxide and after 5 days' interval, they were challenged with 1% ovalbumin solution once every 3 days for total 11 times. Two control groups were studied in parallel, the positive treatment control group was treated with antihistamine and the negative control group was sham-sensitized and sham-challenged. Typical symptoms of allergic rhinitis, such as sneezing, nasal scratching, nasal blockage and rhinorrhea were evaluated. Passive cutaneous anaphylaxis reaction (PCA) was performed to measure the levels of IgG1 and IgE. Eosinophils infiltration and goblet cells in nasal mucosa were observed. In addition, the level of histamine and the number of total leukocytes and eosinophils in the nasal lavage fluid were also measured.

RESULTSIn the model group, symptoms of sneezing, nasal scratching, nasal blockage and rhinorrhea were induced after ovalbumin challenge. The respiratory rate (RR), which reflected the resistance of upper airway, showed a biphasic change. In the PCA test, IgG1 and IgE levels increased after challenges. Eosinophil infiltration in nasal mucosa was more obvious in active groups in comparison to with the negative control group (P < 0.05 or < 0.01). The histamine, total leucocytes and eosinophils levels in nasal lavage fluid also showed higher in the model group (P < 0.05 or < 0.01). The antihistamine treated animals were also induced out above changes but modest compared with the model group (P < 0.05 or < 0.01). The negative control showed few of above changes with significant difference (P < 0.05 or < 0.01).

CONCLUSIONSOur results implied that the modified animal model of allergic rhinitis was capable of showing satisfactory symptomatic and pathophysiological changes in allergic rhinitis. It showed a biphasic nasal blockage with shorter establishment duration. The model also had good treatment reaction to antihistamine. The animal model we introduced may be useful in the study of allergic rhinitis.

Effects of a platelet-released, naturally occurring nucleotide, adenosine 5'-tetraphosphate (ATPP) on vascular tone were analyzed in the isolated rat aorta. Under resting tension ATPP (1 approximately 100 microM) elicited concentration-dependent contractions in endothelium-intact aortic rings in contrast to the concentration-dependent relaxation with ATP. In endothelium-denuded aortic rings, ATPP induced contraction, as ATP did, but with a greater potency. alpha, beta-methylene ATP (APCPP 50 microM), a P2x-purinoceptor antagonist, significantly inhibited ATPP- as well as ATP-induced contractions in the endothelium-denuded preparations suggesting that ATPP acts via P2x-purinoceptors. ATPP (10 approximately 100 microM) relaxed precontracted aortic rings with an intact endothelium in a concentration-dependent manner. This effect of ATPP was 3.7 fold less potent than that of ATP. However, after P2x-purinoceptor blockade, the effect became identical between the two nucleotides. Reactive blue 2, a selective antagonist of P2x-purinoceptors, significantly attenuated the ATPP-induced relaxation with no change in the ATP-induced relaxation. These results indicated that the rat aortic endothelium contains heterogeneous populations of P2-purinoceptors (possibly P2y and nucleotide receptors). Since ATPP shows dual effects depending upon the vascular tension, it may play a significant role in the physiological regulation of vascular tone.
Animal ; Aorta/*drug effects/physiology ; Dinucleoside Phosphates/*pharmacology ; Female ; In Vitro ; Male ; Rats ; Rats, Sprague-Dawley ; Receptors, Purinergic P2/metabolism ; Support, Non-U.S. Gov't ; Vasoconstriction/*drug effects ; Vasodilation/drug effects