Potassium chloride (kcl)

Calcium chloride bihydrate (CaCl₂.2H₂O), magnesium chloride hexahydrate (MgCl₂.6H₂O) and glucose (C₆H₁₂O₆) were purchased from Vetec. Sodium bicarbonate (NaHCO₃) was purchased from Fmaia. Sodium chloride (NaCl) and potassium chloride (KCl) were purchased from Química Moderna. Monopotassium phosphate (NaH₂PO₄), sodium hydroxide (NaOH) and hydrochloric acid (HCl) were purchased from Nuclear. Carbamylcholine hydrochloride (CCh) was purchased from Merck. Formaldehyde was purchased from Vetec. Thiobarbituric acid, tetramethoxypropane, perchloric acid, Mayer's haematoxylin and eosin were purchased from Sigma. Carbogen mixture (95% O₂ and 5% CO₂) was obtained from White Martins (Brazil).
The CCh was used to mimic the cholinergic stimulation that happens on the intestinal smooth muscle promoted by the myenteric plexus [23 (link),24 (link)]. The KCl was employed to simulate the pacemaker of interstitial cells of Cajal located at the boundaries and in the substance of the inner, circular muscle layer, from which they spread to the outer, longitudinal muscle layer [25 ,26 (link)].

The following reference chemicals were obtained from the sources specified: histamine dihydrochloride, carbachol (CCh) (Merck, EUA), Cremophor EL®, S-(-)-Bay K8644, cesium chloride (CsCl), EDTA, HEPES, methylthiotetrazole (MTT), dimethyl sulfoxide (DMSO), penicillin-streptomycin (Sigma-Aldrich, Brazil), ethanol PA (Reagen, Brazil), dulbecco’s modified eagle medium (DMEM), bovine fetal serum, L-glutamine and trypsin/EDTA solution (1:250) (Cultilab, Brazil) and Flou-4 NW dye mix (Invitrogen, EUA).
The following chemicals were used to make the physiological salt solutions: glucose, magnesium sulphate, calcium chloride (Vetec, Brazil), sodium bicarbonate (Fmaia, Brazil), sodium chloride, potassium chloride (Química Moderna, Brazil), monosodium phosphate-1-hydrate, sodium hydroxide and hydrochloric acid (Nuclear, Brazil)
All chemicals used were of the highest purity grade available. Stock solutions of all the chemicals were made in distilled water and the dilutions were made fresh on the day of the experiment.
Carbogen mixture (95 % O₂ and 5 % CO₂) was obtained from White Martins (Brazil).

Luteolin (>98% purity) was purchased from Vicofarma^® (São Paulo, Brazil). Quercetin (IS) (>98% purity) and 75–85% deacetylation degree low molecular weight chitosan (50,000–190,000 Da) were purchased from Sigma Aldrich^® (St. Louis, MO, USA). HPLC-grade formic acid and methanol were purchased from Merck^® (Darmstadt, Germany). HPLC-grade acetonitrile (ACN) was purchased from LiChrosolv^® (Darmstadt, Germany). Monobasic potassium phosphate, sodium pyrophosphate, and oleic acid were purchased from Synth^® (Diadema, Brazil). Hydrochloric acid and acetic acid were purchased from Vetec^® (Duque de Caxias, Brazil). Ketamine and xylazine were purchased from Ceva^® (Paulinia, Brazil). Sodium chloride, sodium hydroxide, ethylene glycol, and dibasic sodium phosphate were purchased from Biotec^® (Lages, Brazil). Potassium chloride was purchased from Química Moderna^® (São Paulo, Brazil). Tween 20 was purchased from Neon Comercial^® (Suzano, Brazil). Ultrapure water was obtained by Millipore^® purification system (Burlington, MA, USA).