| 释义 |
ionotropy Chem.|aɪəˈnɒtrəpɪ|
[f. iono- + Gr. -τροπ-ία turning (f. τρέπειν to turn) + -y3.]
1. Tautomerism or tautomeric change, regarded as occurring through the detachment of an ion from the molecule concerned followed by a redistribution of the charge in the resulting molecular ion and reattachment of the ion to a different part of it. rare.
[1926T. M. Lowry in Inst. Internat. de Chimie Solvay: Deuxième Conseil de Chimie..1925..Rapports et Discussions 151 Les transformations dans lesquelles des radicaux autres que l'hydrogène se déplacent peuvent..être formulées comme comportant une migration d'ions et peuvent être désignées sous le terme d'ionotropie.] 1928Ann. Rep. Progr. Chem. 1927 XXIV. 107 Lowry has also used the word ‘ionotropy’ (Report of the Second Solvay Conference 1925, p. 182). 1955Chem. Abstr. XLIX. 40 Reactions of acids and bases can be described by assuming the fundamental reaction of ‘ionotropy’.
2. [ad. G. ionotropie (H. Thiele 1947, in Naturwiss. XXXIV. 123/2.] The ordering of particles in a gel that results when an electrolyte is added to a colloidal suspension.
1949Chem. Abstr. XLIII. 4539 Usually the sign of the ionotropy is the same as that of flow anisotropy. 1958Jrnl. Physical Chem. LXII. 1277/1 The phenomenon of ionotropy can be simply demonstrated by placing a thin layer of 2% suspension of salt-free Wyoming bentonite on a glass slide and then placing a crystal of sodium chloride on the layer of suspension.
Hence ionoˈtropic a., exhibiting ionotropy (sense 2).
1944Handbk. Descr. in Chem. & Chem. Engin. (U.S. Manpower Comm.) Nov. 66 Polarity, ionotropic change and conjugation. 1954H. Thiele in Discussions Faraday Soc. XVIII. 295 Since ionotropic gels are formed by chemical or electrical forces the degree of order decreases with decreasing dissociation of the ionic groups of the colloid particles. 1969Jrnl. Biomed. Materials Res. III. 432 The ordered ionotropic structure of the fibers of the polyelectrolyte directs the mineralization and calcification in the same manner as in biological tissue.
▸ ionotropic adj. Physiol. (originally) designating a neurotransmitter whose effect is mediated by direct regulation of ion channels; (now usually) designating or relating to a type of cell receptor whose effect is mediated in this way.
1978P. L. McGeer et al. Molecular Neurobiol. Mammalian Brain ii. 141 Neurotransmitters..fall into two categories. The first we refer to as ionotropic because the principal function of the transmitter is to open ionic paths across the postsynaptic membrane. 1982Med. Biol. 60 183 Depending upon the ionotropic or metabotropic characteristics of the cotransmitter, it may be mainly involved in synaptic homeostasis or synaptic plasticity, respectively. 1990Trends in Pharmacol. Sci. 11 254 Ionotropic excitatory amino acid receptors, most notably those activated by NMDA, allow Ca2+ influx as a result of passive diffusion down its concentration gradient. 2004Jrnl. Child Neurol. 19 343 All ionotropic glutamate receptors are believed to be composed of four distinct subunits, each of which is topologically arranged with three transmembrane-spanning and one pore-lining (hairpin loop) domain. |