Molecules 2013, 18(1), 894-913; doi:10.3390/molecules18010894
Article

Dibenzo[1,2,5]thiadiazepines Are Non-Competitive GABAA Receptor Antagonists

1,2, 2, 1, 2, 3email, 4email, 1, 2,* email and 1,* email
Received: 14 December 2012; in revised form: 31 December 2012 / Accepted: 5 January 2013 / Published: 11 January 2013
(This article belongs to the Section Medicinal Chemistry)
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Abstract: A new process for obtaining dibenzo[c,f][1,2,5]thiadiazepines (DBTDs) and their effects on GABAA receptors of guinea pig myenteric neurons are described. Synthesis of DBTD derivatives began with two commercial aromatic compounds. An azide group was obtained after two sequential reactions, and the central ring was closed via a nitrene to obtain the tricyclic sulfonamides (DBTDs). Whole-cell recordings showed that DBTDs application did not affect the holding current but inhibited the currents induced by GABA (IGABA), which are mediated by GABAA receptors. These DBTDs effects reached their maximum 3 min after application and were: (i) reversible, (ii) concentration-dependent (with a rank order of potency of 2c = 2d > 2b), (iii) mediated by a non-competitive antagonism, and (iv) only observed when applied extracellularly. Picrotoxin (which binds in the channel mouth) and DBTDs effects were not modified when both substances were simultaneous applied. Our results indicate that DBTD acted on the extracellular domain of GABAA channels but independent of the picrotoxin, benzodiazepine, and GABA binding sites. DBTDs used here could be the initial model for synthesizing new GABAA receptor inhibitors with a potential to be used as antidotes for positive modulators of these receptors or to induce experimental epilepsy.
Keywords: dibenzothiadiazepines; GABAA receptor antagonists; patch clamp; neurochemistry; biological activity; enteric neurons; electrophysiology
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Ramírez-Martínez, J.F.; González-Chávez, R.; Guerrero-Alba, R.; Reyes-Gutiérrez, P.E.; Martínez, R.; Miranda-Morales, M.; Espinosa-Luna, R.; González-Chávez, M.M.; Barajas-López, C. Dibenzo[1,2,5]thiadiazepines Are Non-Competitive GABAA Receptor Antagonists. Molecules 2013, 18, 894-913.

AMA Style

Ramírez-Martínez JF, González-Chávez R, Guerrero-Alba R, Reyes-Gutiérrez PE, Martínez R, Miranda-Morales M, Espinosa-Luna R, González-Chávez MM, Barajas-López C. Dibenzo[1,2,5]thiadiazepines Are Non-Competitive GABAA Receptor Antagonists. Molecules. 2013; 18(1):894-913.

Chicago/Turabian Style

Ramírez-Martínez, Juan F.; González-Chávez, Rodolfo; Guerrero-Alba, Raquel; Reyes-Gutiérrez, Paul E.; Martínez, Roberto; Miranda-Morales, Marcela; Espinosa-Luna, Rosa; González-Chávez, Marco M.; Barajas-López, Carlos. 2013. "Dibenzo[1,2,5]thiadiazepines Are Non-Competitive GABAA Receptor Antagonists." Molecules 18, no. 1: 894-913.


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