Under certain pathophysiological conditions, such as inflammation and ischemia, the concentration of H+ ion in the tissue surrounding neurons is changed. Variations in H+ concentration are known to alter the conduction and/of the gating properties of several types of ion channels. Several types of K+ channels are modulated by pH. In this study, the whole cell configuration of the patch clamp technique has been applied to the recording of the responses of change of external pH on the delayed rectifier K+ current of cultured DRG neurons of rat. Outward K+ currents were examined in DRG cells, and the Charybdotoxin and Mn2+ could eliminate Ca2+-dependent K+ currents from outward K+ currents. This outward K+ current was activated around -60 mV by step depolarizing pulses from holding potential -70 mV. Outward K+ currents were decreased by low external pH. Activation and steady-state inactivation curve were shifted to the right by acidification, while there was small change by alkalization. These results suggest that H+ could be alter the sensory modality by changing and modifying voltage-dependent K+ currents, which participated in repolarization.
Animals ; Charybdotoxin ; Diagnosis-Related Groups ; Ganglia, Spinal* ; Hydrogen-Ion Concentration* ; Inflammation ; Ion Channels ; Ischemia ; Neurons ; Rats* ; Spinal Nerve Roots*

BACKGROUND: Recently the incidence of coronary artery disease has been increased rapidly in Korea. After the introduction of coronary care unit, the mortality rate of cardiovascular patients has been decreased. The predictive factors for mortality in patients admitted at Coronary Care Unit (CCU) are important in the management of acutely ill cardiovascular patients. METHODS: One thousand one hundred and thirty patients (64.8+/-14.5 years), who were admitted at CCU from January 2002 to June 2003, were analyzed. The patients were divided into two groups according to mortality: the survived group (Group I: n=1055, 63.3+/-13.3 years) and the moribund group (Group II: n=75, 64.8+/-14.1 years). Clinical characteristics, risk factors, clinical diagnosis, laboratory, echocardiographic and coronary angiographic findings were compared between the two groups. RESULTS: The overall mortality at CCU was 6.6%, 75 out of 1130 patients. Age and sex were not different between both groups. Coronary artery disease was the most common cause of admission (886 out of 1130 patients) and death (46 out of 75 patients). Coronary angiographic findings were not different between the two groups. Left ventricular ejection fraction (LVEF) by echocardiogram was higher in Group I than in Group II (53.1+/-15.6% vs. 42.3+/-16.3%, p<0.05). Predictive factors for mortality by multiple logistic regression analysis were low LVEF (OR 11.4, 2.9-21.4 95%CI, p<0.001), no performance of percutaneous coronary intervention (PCI, OR 10.8, 2.5-17.8 95%CI, p<0.001) and clinical diagnosis of aortic dissection (OR 3.8, 1.3-9.8 95%CI, p=0.021). CONCLUSIONS: The predictive factors for mortality at CCU were low LVEF, no PCI and aortic dissection.
Clinical Laboratory Techniques ; Coronary Artery Disease ; Coronary Care Units* ; Coronary Disease ; Diagnosis ; Echocardiography ; Humans ; Incidence ; Korea ; Logistic Models ; Mortality* ; Myocardial Infarction ; Percutaneous Coronary Intervention ; Risk Factors ; Stroke Volume