Type of substance/gas Transporter Location Functions References Small inorganic molecules, that is O2 , CO2 , NO, and H2 O Diffusion Ionic pores/receptors Influx or efflux [47 ] Oxygen Diffusion Ionic pores/receptors Vitality, homeostasis, and cellular metabolism [48 ] Ammonia Passive diffusion Ionic pores/receptors Irritation, toxic [49 ] Nitric oxide Passive diffusion Ionic pores/receptors Toxic [50 ] Water Diffusion and by aquaporins 1–5 Membrane surface aquaporins Controls water relations, regulators of transcellular water flow [51 –54 ] Ethanol By filtration moving through water spaces Ionic pores Alcohol-induced oxidative/nitrosative stress alters brain mitochondrial membrane properties and alters basal extracellular glutamate concentrations and clearance in the mesolimbic system [55 –57 ] Solutes Paracellular or transcellular diffusion Luminal surface Influx or efflux [58 , 59 ] Glucose, hexose (GLUT-1) Facilitated diffusion by GLUT 1 and GLUT 3 Transporters Glucose, morphine-6- -D glucuronide Influx and efflux monosaccharide transport Proteins play important role in carbohydrate assimilation, distribution, metabolism, and homeostasis [44 –46 ] Monocarboxylate Proton linked transport Maintenance of glycolytic metabolism Proliferation of T-lymphocytes [60 , 61 ] Monocarboxylate (MCTI) Facilitated diffusion Benzoic, lactic, lovastatin, and pyruvic acid Influx and efflux promising pharmacological targets including for cancer chemotherapy [61 , 62 ] Anion exchange (band 3) Facilitated diffusion
Cl− / , lactate, and metal-anion com- Influx and efflux Tf-FMMs transferring-conjugated fluorescein loaded magnetic nanoparticles Receptor mediated transcytosis Nanoparticles Influx, drug delivery [63 ] Polycationic proteins and lectins Absorptive-mediated transcytosis Membrane receptors Influx, therapeutic [64 ] Peptide Saturable or facilitated transport and transmembrane diffusion or passive diffusion Membrane receptors Influx, therapeutic [64 ] Saturated fatty acids Facilitated diffusion Octanoate Influx Urea Facilitated diffusion Efflux Xenobiotics Xenobiotics transporters Ionic pores/receptors Out flux, toxicity [65 –67 ] Xenobiotics. 1-methyl-4-phenylpyridinium (MPP+) Uptake2 (Oct1-3/Slc22a1-3, Pmat/Slc29a4), Net, and Mate1/Slc47a1 transporters ATP-driven xenobiotic efflux transporters [35 , 68 , 69 ]