DIDS sodium salt (Synonyms: 4,4'Diisothiocyanato2.2'stilbenedisulfonic acid, MDL 101114ZA)

DIDS is an anion transport inhibitor, which inhibits the ClC-Ka chloride channel with an IC50 of 100 μM and the bacterial ClC-ec1Cl-/H+ exchanger with an IC50 of ~300 μM. [1]
Chloride channels are a superfamily consisting of approximately 13 subgroups and display a variety of functions in physiology. The human genome contains nine CLC proteins, which serve various physiological functions and potentially constitute novel exciting drug targets for the treatment of hypertension, osteoporosis, and gastrointestinal and renal disorders. [1]
DIDS's effect on the calcium-activated chloride current [ICl (ca)] in muscle cells from the rabbit portal vein was studied with the perforated patch technique. Consequently, DIDS reduced the amplitude of spontaneous transient inward currents (STICs) in a concentration-dependent manner with an IC50 value of 2.1 x 10-4 M for STICs. Moreover, DIDS was investigated for its action on contraction of cerebral artery smooth muscle cells. DIDS showed a vasodilator effect on pressure-constricted arteries with IC50 of 69 ± 14 μM. [2, 3]
In vivo study showed DIDS alone increased the effect of hyperthermia at 42.5 ℃ or 43.5 ℃ to suppress tumor growth. The thermosensitization was greater when DIDS was combined with amiloride. Hyperthermia at 43.5 ℃ could result in a tumor growth delay for 4 days, while hyperthermia and treatment of 25 mg/kg DIDS prolonged the delay to approximately 6 days. As a proof, in vivo-in vitro excision assays for cell survival illustrated that DIDS enhanced the heat-induced tumor cell death.  [4]
References:
[1] Wulff, Heike. "New light on the “Old” chloride channel blocker DIDS." ACS chemical biology 3.7 (2008): 399-401.
[2] Hogg, R. C., Q. Wang, and W. A. Large. "Effects of Cl channel blockers on Ca‐activated chloride and potassium currents in smooth muscle cells from rabbit portal vein." British journal of pharmacology 111.4 (1994): 1333-1341.
[3] Nelson, Mark T., et al. "Chloride channel blockers inhibit myogenic tone in rat cerebral arteries." The Journal of Physiology 502.2 (1997): 259-264.
[4] Lyons, John C., Brian D. Ross, and Chang W. Song. "Enhancement of hyperthermia effect in vivo by amiloride and DIDS." International Journal of Radiation Oncology* Biology* Physics 25.1 (1993): 95-103.