ABSTRACT
AIM:To observe the effects of granulocyte colony-stimulating factor (G-CSF) on calcium, sodium and potassium ion channel currents of the ischemic atrial myocytes in guinea pig by whole-cell patch clamp technique.METHODS:The guinea pig atrial myocytes were obtained by enzymolysis.Under ischemia and hypoxia condition, whole-cell patch clamp was used to observe the effects of G-CSF at various concentrations on the changes of the I-V curve, activation curve and availability of L-type calcium channel current (ICa,L) and voltage-dependent sodium channel current (INa), as well as I-V curve of delayed rectifier potassium channel current (IK).RESULTS:Under ischemic condition, the I-V curves of ICa,L were changed by acute G-CSF intervention in a dose-dependent fashion.Except for G-CSF at dose of 300 μg/kg, the other concentrations of G-CSF did not change the activation curve and availability of ICa,L, indicating that the effects of G-CSF on ICa,L were in a voltage-independent fashion.The I-V curves of ICa,L under ischemic condition were gradually approaching the normal levels by the higher dose of G-CSF, while the effect of 300 μg/kg G-CSF on ICa,L was similar to 100 μg/kg G-CSF.Acute G-CSF intervention at different doses did not change I-V curve, activation curve, and availability or steady-state availability of INa.As a part of IK, the rapid activating component (IKr) was improved by 100 μg/kg and 300 μg/kg G-CSF intervention with the similar effects, while the slowly activating component (IKs) was not changed by G-CSF.CONCLUSION:G-CSF affects ion channel electrophysiological properties of ischemic atrial myocytes in a voltage-independent but concentration-dependent manner, thus reducing the incidence of atrial arrhythmia.
ABSTRACT
Objective To observe the effects of granulocyte colony stimulating factor (G-CSF) on electrophysiological properties of post-infarct ventricles.Methods Sixty-seven survival Wistar rats were divided into 4 groups:Sham group,Control group,MI early G-CSF group (E-G) and MI delay G-CSF group (D-G) after ligation of the left coronary artery as myocardial infarction model.Monophasic action potential(MAP) was recorded by absorption electrode in ex vivo perfused rat hearts.Effective refractive period(ERP),sinus cardiac length (SCL),action potential amplitude (APA),maximal depolariged (Vmax),ventricular fibrillation threshold(VFF) and ventricular fibrillation duration(VFD) were measured.Results The electrophysiological parameters (SCL,VFT,VFD,APA,ERP/MAP90,dispersion of ERP and MAP90) of the E-G group were improved significantly (all P ＜ 0.05) at day 7 post MI.Improvement in SCL,dispersion of ERP and MAP 90 were found in the D-G group as well at day 7 post MI (all P ＜ 0.05).Substained improvement in electrophysiological parameters were found in the E-G group at 3 months after MI (P ＜0.05).Besides SCL,APA,Vmax and dispersion of MAP90,all other parameters in the D-G group were similar to that of the control group with no statistical significance and even had a tendency of deterioration in ERP and MAP90 3 months after MI.Conclusion G-CSF intervention could improve electrophysiological properties of ischemic ventricles.Early G-CSF intervention showed better outcomes compared to delay G-CSF intervention on electrical remodeling ischemia myocardiumwhich may have effect on reducing the development of ventricular arrhythmia.
ABSTRACT
Fever model induced by endogenous pyrogen was used to study the effect of needling "Bai hui" point on fever. 126 rabbits served as experimental animal. The present experiment was divided into three parts: Ⅰ. Ⅱ. (injection of pyrogen)and Ⅲ. (no injection), and each part was redivided into experimental (needling "Bai hui" point or "non-channel point) and control (no needling) groups.The findings were: (1) In febrile rabbits induced by endogenous pyrogen, needling "Bai hui" points had significant febrifugal effect, i.e, inhibiting the rise of body temperature, increasing the amplitude of defervescence and accelerating the febrifugal rate. (2) In febrile rabbits, needling "non-channel points" had no marked febrifugal effect, i. e. showing the rise of body temperature, after that, accelerating the febrifugal rate. (3) On body temperature of healthy rabbits, needling "Bai hui" points hnd no hignificant effect.
ABSTRACT
In order to observe the febrffugal response and analysis on its mechanism of needling "Shang gen" point bilateral infraorbital nerves of rabbits were sected in the experiment. Fever models were made by leukocytic pyrogen. The experiment findings were as follows:1. It was found that when febrile response of leukocytic pyrogen in rabbits was significant, the cAMP content in CSF was strikingly increase (25.14?2.11pmol/L). During electric needling "Shang gen" point of febrile rabbits, however, fever response was markedly inhibited (△T was 0.27?0.07 at 60min); The cAMP content rise in CSF was markedly inhibited (11.22?0.13 pmol/ml).2. After sectioning bilateral infraorbital nerves of rabbits, the fever response of febrile rabbits was not depressed (△T was 0.71?0.06 at 60min) during electric needling "Shang gen" point. In the mean time, the cAMP content in CSF was significantly increased (28.53?1.12 pmol/ml).3. The authors inferred that the mechanism of febrffugal response of electric needling "Shang gen" point might be closely associated with producing nerves impulse (from the that point) which inhibited probablely the synthesis of cAMP through some modes.
ABSTRACT
In order to observe the febrifugal response of needling "Chang Qiang Point", and analyse its mechanism lumbar spinal cord of rabbits were damaged in the expermental study. The experimental findings were as follows: 1. It was found that cAMP content in csf was striking increased, when leukocytic pyrogen fever of rabbits was significant. During needling "Chang Qiang Point" of febrile rabbits, however, febrile response was markedly inhibited(at 60 min~?T℃ was 0.23?0.07 and TRI4 0.61?0.03). There was significant difference(P0.05). 3. After damaging lumbar spinal cord of rabbits, there were certain change of rectal temperature and the febrile response, but it had no effect on cAMP content in csf. The authors infered that the impulses from "Chang Qiang Point" transmiled Via spinal cord might be closely associated with reflex mechanism and the change of cAMP content might play an important role in the mechanism of febrifugal effect during needling "Chang Qiang Point" in febrile rabbits.
ABSTRACT
In order to analyze the mechanism of febrifugal effect of electric needling "Baihui (Hundreds Converge)" point of febrile rabbits, 108 rabbits were divided into 5 groups, serveing as experimental animals. The results obtained showed: 1. In febrile rabbits induced by monoeytic pyrogen, electric needling "Bai hui" points has significant febrifugal effect, i. e. inhibiting the rise of body temperature, in the meantime the cAMP content rose in c. s. f. was markedly inhibited. 2. On febrile rabbits, electric needling blocking "Bai hui" point and Non-acupoint exhibited no marked febrifugal effect, i. e. showing apparently fever response, and at the same time cAMP contents in c. s. f. was strikingly increased. 3. Blocking of "Bai hui" point itself did not produce any effect on pyrogen-induced fever and cAMP content increased.The author inferred that the mechanism of inhibitory effect of electric needling "Bai hui" points in febrile rabbits might be closele assocated with feeling of local sensible tissue (e. g. free nerve endings) in "Bai hui" point, and with producing nerve impuls which transmitted through some mode to brain. As a result, increased cAMP was inhibited and setpoint to move up was inhibited.
ABSTRACT
In 100 rabbits, the febrifugal effect of needling on the endogenous pyrogen fever was studied. These experiments were divided into two parts:Part Ⅰ: Influence of acupoint block on the needling febrifugal effect of rabbit. Eighty rabbits were redivided into 4 groups. Group Ⅰ was with blocking of acupoint "Bai Hui (Hundreds Converge)". In this group, the febrile rabbits were needled after blocking "Bai hui" point with lidocaine (hydrochloride). Group Ⅱ was a group of needling "Bai hui". GroupⅢ was a control group of febrile rabbits. In all the above three groups, febrile effect was induced by intravenous injection of 10ml supernatant containing endogenous pyrogen (Ep). Group Ⅳ was a blank control.Part Ⅱ: Influence of acupoint block on the febrile effect of rabbit. Twenty rabbits were divided into experimental (acupoint block) and control (no block) groups.It was found that needling "Bai hui" point of febrile rabbits would produce marked febrifugal effect, while little febrifugal effect could be observed by needling blocked "Bai hui" point of febrile rabbits. The difference was significant (P