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  • T200 - (1,2,5,6-Tetrahydropyridin-4-yl)methylphosphinic acid hydrate

T200 Sigma-Aldrich

(1,2,5,6-Tetrahydropyridin-4-yl)methylphosphinic acid hydrate

≥97% (HPLC), solid

Synonym: TPMPA hydrate

  • CAS Number 182485-36-5 (anhydrous)

  • Empirical Formula (Hill Notation) C6H12NO2P · xH2O

  • Molecular Weight 161.14 (anhydrous basis)

  •  PubChem Substance ID 24278172

  •  NACRES NA.77



Related Categories Antagonists, Bioactive Small Molecule Alphabetical Index, Bioactive Small Molecules, Cell Biology, Cell Signaling and Neuroscience,
Quality Level   100
assay   ≥97% (HPLC)
form   solid
color   white to off-white
solubility   H2O: 16 mg/mL
  DMSO: insoluble
SMILES string   [H]O[H].CP([O-])(=O)C1=CC[NH2+]CC1
InChI   1S/C6H12NO2P.H2O/c1-10(8,9)6-2-4-7-5-3-6;/h2,7H,3-5H2,1H3,(H,8,9);1H2



(1,2,5,6-Tetrahydropyridin-4-yl)methylphosphinic acid hydrate has also been used as γ-aminobutyric acid C (GABAc) blocker in retinal ganglion cells.

TPMA has been used as a GABAC receptor antagonist to study the role of inner retinal inhibition in midget ganglion cells. TPMPA has also been used to study the role of GABAC receptor antagonists in suppressing orientation selectivity in ganglion cells.


10, 50 mg in glass bottle

Biochem/physiol Actions

TPMPA is a hybrid of isoguvacine and 3-APMPA designed to retain affinity for GABAC receptors but not to interact with GABAA or GABAB receptors. Electrical assays show that TPMPA is a competitive antagonist of cloned human mu 1 GABAC receptors expressed in Xenopus laevis oocytes (Kb approx. 2 μM). TPMPA is >100-fold weaker as an inhibitor of rat brain GABAA receptors expressed in oocytes (Kb approx. 320 μM) and has only weak agonist activity on GABAB receptors assayed in rat hippocampal slices (EC50 approx. 500 μM). TPMPA may be used to investigate GABAC receptor function in the outer retina and in any other areas of the nervous system in which these types of receptor are present.

Features and Benefits

This compound is a featured product for Neuroscience research. Click here to discover more featured Neuroscience products. Learn more about bioactive small molecules for other areas of research at sigma.com/discover-bsm.

This compound is also offered as part of Sigma′s Library of Pharmacologically Active Compounds (LOPAC®1280), a biologically annotated collection of high-quality, ready-to-screen compounds. Click here to learn more.

This compound is featured on the GABAC Receptors page of the Handbook of Receptor Classification and Signal Transduction. To browse other handbook pages, click here.

Preparation Note

(1,2,5,6-Tetrahydropyridin-4-yl)methylphosphinic acid (TPMPA) hydrate is soluble in water at 16 mg/ml, but is insoluble in DMSO.

Legal Information

Sold in the USA under exclusive license from the University of California.

LOPAC is a registered trademark of Sigma-Aldrich Co. LLC

Safety & Documentation

Safety Information

Personal Protective Equipment 
NONH for all modes of transport
WGK Germany 
Flash Point(F) 
Not applicable
Flash Point(C) 
Not applicable


Certificate of Analysis (COA)

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Protocols & Articles


Discover Bioactive Small Molecules for Neuroscience

The nervous system, comprised of the brain and spinal cord (central nervous system, or CNS) and network of nerves that connects the CNS to the rest of the body (peripheral nervous system, or PNS) is ...
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