The systematic measurements of densities (rho) and speeds of sound (u) of aqueous binary mixtures of bioactive amino acid neurotransmitters viz, gamma amino butyric acid, glycine hydrochloride and sodium glutamate at different temperatures i.e. T = (278.15, 288.15 and 298.15) K within the concentration range of (0.05 to 0.35) mol . kg(-1) have been carried out. The obtained data of densities and speeds of sound were used to calculate different derived parameters such as apparent molar volume of solute (V-phi), isentropic compressibility of solution (kappa(s)) and apparent molar isentropic compressibility of solute (kappa(phi)) of gamma amino butyric acid, glycine hydrochloride and sodium glutamate in water at different temperatures. The limiting values of apparent molar volume (V-phi(0)) of solute, apparent molar isentropic compressibility (kappa(0)(phi)) of solute and apparent molar expansivity (E-phi(0)) have also been obtained. The coefficient of thermal expansion (alpha*), second derivative of limiting apparent molar volume (partial derivative V-2(phi)0/partial derivative T-2) and hydration number (n(H)) of the water soluble neurotransmitters have also been computed. The results have been interpreted in terms of various interactions among solute and solvent molecules such as hydrogen bonding, (solute + solute) and (solute + solvent) interactions and structure making and structure breaking tendencies of the solutes in water. The scaled particle theory has been used to interpret volumetric results. (C) 2015 Elsevier Ltd. All rights reserved.