. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 346 ELLIS, THIENES, AND WIERSMA An interesting demonstration of the after-discharge of the excitor was seen on releasing inhibition shortly after stimulation of the excitor was discontinued. The resulting contraction could only be due to such an after-discharge. Combined repetitive activity or after-discharge of both inhibitor and excitor would result in a situation so nearly normal that no clear- cut differences could be observed. In several instances treatment with hydrastinine (1%) was accom- panied by a state in which fa
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 346 ELLIS, THIENES, AND WIERSMA An interesting demonstration of the after-discharge of the excitor was seen on releasing inhibition shortly after stimulation of the excitor was discontinued. The resulting contraction could only be due to such an after-discharge. Combined repetitive activity or after-discharge of both inhibitor and excitor would result in a situation so nearly normal that no clear- cut differences could be observed. In several instances treatment with hydrastinine (1%) was accom- panied by a state in which faradic stimulation of the inhibitor resulted in an enhancement of excitation, or even in contraction of the opener muscle in the absence of stimulation of the excitor (Figure 6). This. FIGURK 6. Mechanogram of the opener muscle of Cambarus clarkn after treat- ment with hyclrastinine hydrochloride, showing reversal of inhibitor. The excitor and inhibitor were isolated so as to prevent stimulation by current escape. T = 1 second, E = excitatory stimulation, I = inhibitory stimulation. effect was also obtained following injection of pyrethrum () into the claw. It should be pointed out that due care was taken in each case to avoid stimulation of the other fibers by current escape. An explanation of this interesting phenomenon will be given in the discussion. .Supplementary inhibition. The presence of an independent sec- ondary inhibitory process (supplementary inhibition) resulting in a depression of the muscle action potentials has made it interesting to investigate the effects of the drugs on this process. Supplementary inhibition occurs only when the time of arrival at the muscle of the inhibitory impulse just precedes that of the excitatory impulse within a very narrow time interval. When yohimbine was used it was found that with concentrations which were just high enough to ultimately produce the characteristic block of excitation, supplementary inhibi-. Please note that t
Size: 2636px × 948px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
