Tetraethylammonium chloride

Tetraethylammonium chloride (TEAC) is a quaternary ammonium compound, which has been used as the source of tetraethylammonium ions in pharmacological and physiological studies.

In vitro: Tetraethylammonium (TEA) is a small ion that is thought to block open K channels by binding either to an internal or to an external site. For this reason, it has been used to probe the ion conduction pathway or pore of K channel mutants and a K channel chimera. TEA blocks K+ channels at two sites, which define the inner and outer mouths of the channel pores [1].

In vivo: Vasorelaxant effect of taurine can be diminished by TEA in rat isolated arteries [2]

Clinical trial: TEAC blocks both sympathetic and parasympathetic transmission at the ganglia. TEAC can relieve the pain of coronary artery disease. By the use of TEAC, the symptoms of Buerger's disease seem to be meliorated, at least temporarily. TEAC appears to be of little value in advanced arteriosclerotic diseases [3].

References:
[1] Taglialatela M, Vandongen AM, Drewe JA, Joho RH, Brown AM, Kirsch GE.  Patterns of internal and external tetraethylammonium block in four homologous K+ channels. Mol Pharmacol. 1991 Aug;40(2):299-307.
[2] Niu LG, Zhang MS, Liu Y, Xue WX, Liu DB, Zhang J, Liang YQ.  Vasorelaxant effect of taurine is diminished by tetraethylammonium in rat isolated arteries. Eur J Pharmacol. 2008 Feb 2;580(1-2):169-74. Epub 2007 Oct 25.
[3] SHEA PA, DUNKLEE PE, et al.  Preliminary clinical investigation of tetraethylammonium chloride with particular reference to disorders of the circulatory system. Calif Med. 1948 Sep;69(3):193-6.

Tetraethylammonium and 4-aminopyridine block calcium-dependent chloride current in rat cerebellum Purkinje cells.[Pubmed:27817032]

Dokl Biochem Biophys. 2016 Sep;470(1):332-334.

Using patch-clamp method (whole cell configuration), it was shown that tetraethylammonium (TEA) and 4-aminopyridine (4-AP) block calcium-dependent chloride currents in the membrane of freshly isolated cerebellar Purkinje cells of rats (12-15 days). In the concentration range studied (50 muM-10 mM TEA and 100 muM-1 mM 4-AP), both compounds blocked the chloride current at IC50 130 muM for TEA and 110 muM for 4-AP. TEA blockade was reversible after washing. The effect of 4-AP at concentrations greater than 100 muM was irreversible: both outward and inward chloride currents were blocked even after the removal of 4-AP from the incubation medium.

Effects of tetramethyl- and tetraethylammonium chloride on H2O: calorimetric and near-infrared spectroscopic study.[Pubmed:23249405]

J Phys Chem B. 2013 Jan 24;117(3):877-83.

The effect of Tetraethylammonium chloride (TEAC) on H(2)O was investigated by the 1-propanol (1P) probing thermodynamic methodology developed by us earlier. It was found that TEAC is an amphiphile with a small hydrophobic and a dominant hydrophilic contribution. An earlier application of the same 1P-probing methodology to tetramethylammonium chloride (TMAC) indicated that the latter is as hydrophilic as urea without any hydrophobic contribution. The hydrophilic effect of TEAC was found to be about twice stronger than that of TMAC. To investigate further these surprising findings, we applied a new analysis method using the concept of the excess partial molar absorptivity of the solute on the nu(2) + nu(3) combination band of H(2)O in the near-infrared (NIR) range of their aqueous solutions. The results confirmed that both salts are indeed strongly hydrophilic toward H(2)O which manifests itself in the 5123 cm(-1) chromophore of the NIR band of H(2)O. Furthermore, we suggest from the behavior of the 5263 cm(-1) band that both solutes might form small aggregates in the H(2)O-rich region of the respective aqueous solutions.

Evaluation of the effect of tetraethylammonium bromide and chloride on the growth and development of terrestrial plants.[Pubmed:26844662]

Chemosphere. 2016 Apr;149:24-33.

Quaternary ammonium salts (QAS), which also include ionic liquids, constitute a vast group of chemical compounds that are increasingly common in the commercial use. This situation may lead to the contamination of the natural environment and may constitute a potential threat to all its elements, including terrestrial higher plants. This paper presents the effect of Tetraethylammonium chloride [TEA][Cl] and tetraethylammonium bromide [TEA][Br] on the growth and development of spring barley and common radish. The applied QAS were characterized with phytotoxicity dependent on the concentration of compound and characteristics of the study plants. Spring barley turned out to be highly susceptible plant to the analyzed compounds, which was confirmed by % inhibition of length of plants, root length and fresh weight of plants and by calculated values for EC50, NOEC as well as LOEC. On the contrary, a common radish revealed the resistance to QAS used in the study; although, phytotoxic symptoms were still observed when high concentrations of dry weight of soil were applied (1000, 3000 and 5000 mg/kg). The applied QAS caused oxidative stress symptoms, mainly in spring barley seedlings, which were manifested by decreased assimilation of pigments content, increased hydrogen peroxide (H2O2) and malondialdehyde (MDA) content in plant cells and with a changed activity of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD).

Comparison of the L-glutamate level in mouse hippocampal slices under tetraethylammonium chloride stimulation as measured with a glass capillary sensor and a patch sensor.[Pubmed:19276590]

Anal Sci. 2009 Mar;25(3):353-8.

The concentration level of L-glutamate released from the region CA1 of mouse hippocampal slices under Tetraethylammonium chloride (TEA) stimulation was measured by two independent methods, i.e., a glass capillary-based enzyme sensor and a patch sensor, and compared with each other for different slice preparations. In a submerged slice preparation, the sensors were positioned in bath solutions several tens microm above CA1, respectively. The sensors exhibited almost the same level of extra-slice L-glutamate concentration. When a capillary sensor was implanted in region CA1 at a depth of approximately 10 microm, the TEA-induced L-glutamate release pattern was very similar to those observed with the capillary sensor in a bath use. The concentration level of intra-slice (extracellular) L-glutamate was found to be in the range from 6 to 10 microM, which was significantly larger than that of the extra-slice one. These results demonstrate that L-glutamate released from each neuronal region inevitably diffuses out of the slices, and the extra-slice L-glutamate level reflects the extracellular one.

Vasorelaxant effect of taurine is diminished by tetraethylammonium in rat isolated arteries.[Pubmed:17997400]

Eur J Pharmacol. 2008 Feb 2;580(1-2):169-74.

Although the vasorelaxant effects of taurine have been studied in rabbit ear artery, rat isolated aorta and mesenteric artery, its pharmacological properties in other vascular beds and underlying mechanism(s) are still not well clarified. The present study was designed to observe the effects of taurine on the contractions induced by depolarization and phenylephrine in rat isolated aortic, renal and mesenteric arterial rings, and to get an insight into its mechanism(s). Arterial rings were suspended in organ baths and tension was recorded isometrically. Taurine 20-80 mM produced concentration-dependent relaxations of rat isolated aortic rings precontracted by 30 mM potassium chloride and 1 microM phenylephrine; the maximal relaxation was 17.17+/-3.18% and 22.23+/-1.83% respectively. The relaxation was not affected by 0.1 mM NG-nitro-L-arginine methylester ester (a nitric oxide synthetase inhibitor), 10 microM indomethacin (a cyclooxygenase inhibitor), 1 mM 4-aminopyridine (a K(V) blocker), 10 muM glibenclamide (a K(ATP) blocker), 1 mM barium chloride (BaCl(2), a K(IR) blocker), and 100 nM iberiotoxin (a BK(Ca) blocker), but was nearly abolished by 10 mM tetraethylammonium (TEA, a non-selective potassium channel blocker). Preincubation with taurine 20-60 mM did not affect the basal tone but inhibited the contraction induced by phenylephrine, and the inhibitory effect was attenuated by TEA in isolated renal and mesenteric arterial rings. Present experiments show that taurine relaxes contracted rat aorta and inhibits the phenylephrine-induced contraction of renal and mesenteric arteries, and suggest that a mechanism related to potassium channel opening may be involved in the action of taurine.