The effects of Nω-nitro-L-arginine methyl ester(L-NAME)i.v.and nitric oxide(NO) inhalation on integrated systemic responses to cocaine were studied in lightly anesthetized, paralyzed, and mechanically ventilated rats...The effects of Nω-nitro-L-arginine methyl ester(L-NAME)i.v.and nitric oxide(NO) inhalation on integrated systemic responses to cocaine were studied in lightly anesthetized, paralyzed, and mechanically ventilated rats.Cocaine [4 mg/(kg. min) i.v.] produccd seizures then isoelectric electrocephalographic(isoEEG)activity as well as an initial increase in systolic blood pressure and heart rate,then progressive cardiovascular system depression culminating in asystole. Pretreatment with L-NAME[2 mg/(kg. min)i.v. ] for 30 min significantly reduced the incidence of seizure as compared to saline treated animals (saline 7/8; L-NAME 3/8).Doses of cocaine that produced arrhythmias, isoEEG and asystole were significantly lower in the L-NAME treated animals as compared to the saline group. L-NAME did not affect peak systolic blood pressure and heart rate responses to cocaine. NO inhalation(80 ppm)did not affect CNS and cardiovascular responses to cocaine in control animals but enhanced the effects of L-NAME on cocaine toxicity. The results show that pretreatment with L-NAME reduces the central nervous system stimulatory effect of cocaine (reduced seizure incidence) and enhances its depressant effect on both the central nervous system (lower does for isoEEG) and the cardiovascular stimulatory action of cocaine. NO inhalation does not protect against any of the systemic effects of cocaine in animals with normal or suppressed NO production.展开更多
Yttrium(Ⅲ)oxide or so-called diyttrium trioxide(Y_2O_3)is an excellent candidate ceramic material for optoelectronic applications.Structural,electrical conductivity,and dielectric relaxation properties of bulk yttri...Yttrium(Ⅲ)oxide or so-called diyttrium trioxide(Y_2O_3)is an excellent candidate ceramic material for optoelectronic applications.Structural,electrical conductivity,and dielectric relaxation properties of bulk yttrium(Ⅲ)oxide were studied.X-ray diffraction(XRD)results indicate that the yttrium(Ⅲ)oxide compound has a crystalline cubic phase.Fourier transform infrared(FTIR)technique was used to ascertain the chemical structure of the yttrium(Ⅲ)oxide compound.Impedance spectroscopy was used to analyze frequency-dependent electrical properties as a function of temperature in the range of 303-423 K and frequency range of 0.1 Hz-2 MHz.Impedance spectroscopy parameters such as dielectric constant,dielectric loss,loss factor,electric modulus,and complex impedance of the yttrium(Ⅲ)oxide compound were studied.The Nyquist plot describes the complex impedance of the yttrium(Ⅲ)oxide for different temperatures.The universal Jonscher's power law was used for the analysis of the complex electrical conductivity of the yttrium(Ⅲ)oxide compound.It is found that the real(σ')and imaginary(σ")parts of the complex conductivity increase with increasing frequency.The exponent frequency(s)equals unity,which confirms that the predominant conduction mechanism is a nearly constant loss(NCL)mechanism.DFT/TD-DFT studies using B3LYP/LanL2DZ level of theory were used to provide comparable theoretical data and electronic energy gap of HOMO→LUMO.展开更多
文摘The effects of Nω-nitro-L-arginine methyl ester(L-NAME)i.v.and nitric oxide(NO) inhalation on integrated systemic responses to cocaine were studied in lightly anesthetized, paralyzed, and mechanically ventilated rats.Cocaine [4 mg/(kg. min) i.v.] produccd seizures then isoelectric electrocephalographic(isoEEG)activity as well as an initial increase in systolic blood pressure and heart rate,then progressive cardiovascular system depression culminating in asystole. Pretreatment with L-NAME[2 mg/(kg. min)i.v. ] for 30 min significantly reduced the incidence of seizure as compared to saline treated animals (saline 7/8; L-NAME 3/8).Doses of cocaine that produced arrhythmias, isoEEG and asystole were significantly lower in the L-NAME treated animals as compared to the saline group. L-NAME did not affect peak systolic blood pressure and heart rate responses to cocaine. NO inhalation(80 ppm)did not affect CNS and cardiovascular responses to cocaine in control animals but enhanced the effects of L-NAME on cocaine toxicity. The results show that pretreatment with L-NAME reduces the central nervous system stimulatory effect of cocaine (reduced seizure incidence) and enhances its depressant effect on both the central nervous system (lower does for isoEEG) and the cardiovascular stimulatory action of cocaine. NO inhalation does not protect against any of the systemic effects of cocaine in animals with normal or suppressed NO production.
基金supported by Taif University Researchers,Taif University,Taif,Saudi Arabia(grant numbers TURSP-2020/22)。
文摘Yttrium(Ⅲ)oxide or so-called diyttrium trioxide(Y_2O_3)is an excellent candidate ceramic material for optoelectronic applications.Structural,electrical conductivity,and dielectric relaxation properties of bulk yttrium(Ⅲ)oxide were studied.X-ray diffraction(XRD)results indicate that the yttrium(Ⅲ)oxide compound has a crystalline cubic phase.Fourier transform infrared(FTIR)technique was used to ascertain the chemical structure of the yttrium(Ⅲ)oxide compound.Impedance spectroscopy was used to analyze frequency-dependent electrical properties as a function of temperature in the range of 303-423 K and frequency range of 0.1 Hz-2 MHz.Impedance spectroscopy parameters such as dielectric constant,dielectric loss,loss factor,electric modulus,and complex impedance of the yttrium(Ⅲ)oxide compound were studied.The Nyquist plot describes the complex impedance of the yttrium(Ⅲ)oxide for different temperatures.The universal Jonscher's power law was used for the analysis of the complex electrical conductivity of the yttrium(Ⅲ)oxide compound.It is found that the real(σ')and imaginary(σ")parts of the complex conductivity increase with increasing frequency.The exponent frequency(s)equals unity,which confirms that the predominant conduction mechanism is a nearly constant loss(NCL)mechanism.DFT/TD-DFT studies using B3LYP/LanL2DZ level of theory were used to provide comparable theoretical data and electronic energy gap of HOMO→LUMO.
