Spadin TFA, a natural peptide extracted from a propeptide released in the blood, is a potent TREK-1 channel blocker with IC50 of 10 nM. Spadin TFA enhances 5-HT neurotransmission in the dorsal raphe nucleus and induces hippocampal CREB activation and neurogenesis in mice. Spadin TFA may be used in antidepressant research.

Physicochemical Properties

Molecular Formula	C92H143F3N26O24
Molecular Weight	2126.36
Related CAS #	Spadin;1270083-24-3
Appearance	White to off-white solid powder
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	The spadin inhibitory effect on TREK-1 channels is exhibited by spadin TFA (100 nM; COS-7 cells), which also blocks 63% of TREK-1 currents induced by arachidonic acid [1]. In wild-type mouse brain slices, spadin TFA (100 nM) inhibits TREK-1 channel activity in CA3 hippocampal neurons [1].
ln Vivo	In the dorsal raphe nucleus (DRN), spadin TFA (10 μM, 100 μL; i.p.; 30 min; male C57Bl/6J and TREK-1-deficient mice) enhances the rate at which 5-HT neurons fire [2]. The antidepressant effects of spadin TFA (0.01-100 μM, 100 μL; intracerebroventricular, intraperitoneal, and ICV; daily for 7 days; male C57Bl/6J and TREK-1-deficient mice) have been observed in mice [2].
Animal Protocol	Animal/Disease Models: Male C57Bl/6J and TREK-1 deficient mice[2] Doses: 10 μM Route of Administration: intraperitoneal (ip)injection; for 30 min Experimental Results: Increased of the 5-HT neuron firing rate in the dorsal raphe nucleus (DRN). Animal/Disease Models: Male C57Bl/6J and TREK-1 deficient mice[2] Doses: 0.01-100 μM Route of Administration: Intracerebroventrical injection (100 nM), intraperitoneal (ip)injection (1-100 μM) and intravenous (iv) injection (0.01-1 μM); daily, for 7 days Experimental Results: Had any effect on mouse locomotion analyzed in short- or long-time after the drug injection.
References	[1]. Targeting two-pore domain K(+) channels TREK-1 and TASK-3 for the treatment of depression: a new therapeutic concept. Br J Pharmacol. 2015 Feb;172(3):771-84. [2]. Spadin, a sortilin-derived peptide, targeting rodent TREK-1 channels: a new concept in the antidepressant drug design. PLoS Biol. 2010 Apr 13;8(4):e1000355.

Solubility Data

Solubility (In Vitro)

H2O :~25 mg/mL (~11.76 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (1.18 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (1.18 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 2.5 mg/mL (1.18 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly. Solubility in Formulation 4: 50 mg/mL (23.51 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with ultrasonication.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	0.4703 mL	2.3514 mL	4.7029 mL
	5 mM	0.0941 mL	0.4703 mL	0.9406 mL
	10 mM	0.0470 mL	0.2351 mL	0.4703 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.