镧和铥对大鼠输精管力学反应的影响。

The effects of lanthanum and thulium on the mechanical responses of rat vas deferens.

Swamy V C, Triggle C R, Triggle D J

J Physiol. 1976 Jan;254(1):55-62. doi: 10.1113/jphysiol.1976.sp011220.

Abstract

The contractile responses of rat vas deferens to noradrenaline and K+ are composed of phasic and tonic components both of which are dependent upon the concentration of extracellular Ca2+. 2. Lanthanum, La3+, and thulium ions, Tm3+, inhibited the noradrenaline and K+ induced responses, complete inhibition being obtained at approximately 10(-3) M-Ln3+. 3. La3+ and Tm3+ were equally effective in inhibiting noradrenaline and K+ responses. The phasic and tonic components of the noradrenaline response were equally sensitive to lanthanide cations, Ln3+, but the phasic component of the K+ response was more sensitive than the tonic component. 4. 170Tm binding did not show any saturable component over the concentration range in which inhibition of the pharmacological response was obtained. 5. It is suggested that the actions of Ln3+ in the rat vas deferens are mediated through some kind of membrane stabilization rather than via a specific Ca2+ binding site concerned with excitation-contraction coupling, the mechanism previously postulated for the Ln3+ action in guinea-pig ileal longitudinal muscle.

摘要

大鼠输精管对去甲肾上腺素和K⁺的收缩反应由相性和紧张性成分组成，二者均依赖于细胞外Ca²⁺的浓度。2. 镧（La³⁺）和铥离子（Tm³⁺）抑制去甲肾上腺素和K⁺诱导的反应，在约10⁻³ M-Ln³⁺时可获得完全抑制。3. La³⁺和Tm³⁺在抑制去甲肾上腺素和K⁺反应方面同样有效。去甲肾上腺素反应的相性和紧张性成分对镧系阳离子（Ln³⁺）同样敏感，但K⁺反应的相性成分比紧张性成分更敏感。4. 在获得药理反应抑制的浓度范围内，¹⁷⁰Tm结合未显示任何饱和成分。5. 提示Ln³⁺在大鼠输精管中的作用是通过某种膜稳定作用介导的，而非通过与兴奋-收缩偶联相关的特定Ca²⁺结合位点，这是先前推测的Ln³⁺在豚鼠回肠纵肌中作用的机制。