摘要:

The dose-response relationship, onset, duration of action, atropine requirement, and pharmacokinetic variables of edrophonium were determined in infants and children during N2O–halothane anesthesia. The technique of steady state infusion ofd-tubucurarine (dTc) was used to determine the ED50for edrophonium (i.e., the dose producing 50% antagonism of 90% neuromuscular depression) in 14 infants (145 μg/kg) and 12 children (233 μg/kg). The reported values for ED50for edrophonium (obtained under similar anesthetic conditions) is 128 μg/kg for adults. These three dose–response curves do not differ statistically; however, there was greater variability among infants and children than adults. Time to peak antagonism was similar for all three age groups. Duration of antagonism was determined in six infants and six children and did not differ from the reported value for adults. The optimal dose and time of administration of atropine were established by administering edrophonium (1 mg/kg) and atropine (10–20 μg/kg) to 24 infants and children. The smallest changes in heart rate and systolic blood pressure occurred when atropine (10 μg/kg) was givne 30 s before edrophonium. The pharmacokinetics of edrophonium (1 mg/kg) were studied in four infants and four children and were compared with published values for adults: distribution and elimination half-lives and distribution volumes were similar for the three groups. Total clearance (ml · kg-1· min-1) was greatest for infants (17.8 ± 1.2) compared with children (14.2 ± 7.3) and adults (8.3 ± 2.9). The authors conclude that the dose of edrophonium required to antagonize dTc-induced neuromuscular blockade is similar or possibly greater for infants and children than for adults. Onset and duration of antagonism are similar for all three age groups, despite age-related differences in total clearance. Edrophonium, 1 mg/kg, appears to antagonize neuromuscular blockade effectively in infants and children; cardiovascular changes can be minimized by administering atropine (10 μg/kg) 30 s before edrophonium.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

Local rates of glucose utilization in the spinal cord and brain were measured with the 2-[14C]deoxyglucose method in conscious and in paralyzed and mechanically ventilated pentobarbital- or 70% nitrous oxide-treated rats. In conscious animal lumbar spinal cord glucose utilization is only 40–50% that of the cerebral cortex and shows little laminar heterogeneity. Pentobarbital reduces and nitrous oxide increases the cerebral glucose utilization of most structures. The effect of paralysis and nitrous oxide analgesia on lumbar spinal cord glucose utilization is quantitatively similar to that produced in brain; 15–25% increases occur in most spinal cord laminae and cerebral structures. In contrast, the 10–20% reduction in spinal cord gray matter metabolism in the paralyzed and pentobarbital-treated animals is considerably less than the 20–50% depression measured in most brain structures. From these data the authors conclude that, relative to that of most cerebral structures, spinal cord metabolism is less sensitive to depression by barbiturates and suggest that differences in the cell populations of these tissues may account partially for this observation.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

摘要:

The effects of volatile anesthetics upon the function of bovine rhodopsin were estimated from the measurements of light-induced proton uptake. The light-inducedpH changes were measured at both 20° C and 37° C with suspensions to which volatile anesthetics were added in the liquid form. Each anesthetic depressed the light-induced proton uptake concentration-dependently. The anesthetic-induced depression was greater at 37° C than at 20° C. For each anesthetic the concentration needed to depress the proton uptake by 10% was roughly identical to that used clinically. Anesthetics also were added to the suspensions in the gaseous form with air. The light-induced proton uptake was decreased in proportion to the partial pressure of the anesthetic. The partial pressures of halothane and methoxyflurane that depressed the proton uptake by 10% at 37° C were 2.0 X 10-2and 1.1 X 10-2atm., respectively. From these facts it is suggested that volatile anesthetics affect the light-induced conformational changes of rhodopsin molecule during the metarhodopsin I to metarhodopsin II transition and cause inhibition of the light-induced proton uptake of rhodopsin in the rod outer segment disk membrane.

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID

ISSN:0003-3022    

出版商:OVID    

年代:1984

数据来源: OVID