Comparative NMR studies of diffusional water permeability of red blood cells from different species XV. Agile wallaby (Macropus agilis), red-necked wallaby (Macropus rufogriseus) and Goodfellow's tree kangaroo (Dendrolagus goodfellowi)

The water diffusional permeability (P-d) of red blood cells (RBC) from agile wallaby (Macropus agilis), red-necked wallaby (Macropus rufogriseus) and Goodfellow's tree kangaroo (Dendrolagus goodfellowi) was monitored using an Mn2+-doping H-1 nuclear magnetic resonance (NMR) technique at 400 MHz. The P-d (cm s(-1)) values of agile wallaby RBCs were 7.5 x 10(-3) at 25 degrees C, 9 x 10(-3) at 30 degrees C, 11 X 10(-3) at 37 degrees C, and 13 x 10(-3) at 42 degrees C. The inhibitory effect of a mercury-containing sulfliydryl (SH)-modifying reagent p-chloromercuribenzoate (PCMB) on agile wallaby RBCs was investigated. The maximal inhibition was reached in 90 min at 37 degrees C with 2 mmol L-1 PCMB. The value of maximal inhibition was similar to 63% when measured at 25 degrees C, similar to 52% at 37 degrees C and degrees 45% at similar to 42 degrees C. The lowest value of Pd (corresponding to the basal permeability to water) was similar to 3 x 10(-3) cm s(-1) at 25 degrees C. For the RBCs from red-necked wallaby (M. rufogriseus) the values of Pd (cm s(-1)) were 7 x 10(-3) at 25 degrees C, 8 x 10(-3) at 30 degrees C, 10 x 10(-3) at 37 degrees C, and 12 x 10(-3) at 42 degrees C. Higher values of Pd (cm s-1) were found for the RBCs from Goodfellow's tree kangaroo (D. goodfellowi): 8.5 x 10(-3) at 25 degrees C, 10 X 10(-3) at 30 degrees C. 13 x 10(-3) at 37 degrees C, and 15 x 10(-3) at 42 degrees C. The mean values of the activation energy of water diffusion (E-a.d) were similar to 25 kJ mol(-1) for RBCs from the agile wallaby and tree kangaroo, respectively, and similar to 23 kJ mol(-1) for RBCs from red-necked wallaby. The values of E-a,E-d increased after exposure of agile wallaby RBCs to PCMB, reaching a value of similar to 43-46 kJ mol(-1) when the maximal inhibition of Pd was achieved. (C) 2009 Elsevier Inc. All rights reserved.