THE EFFECTS OF ANESTHESIA AND PHYSICAL RESTRAINT ON INTRACELLULAR ANDEXTRACELLULAR TUMOR PH, TUMOR TEMPERATURE AND BIOENERGETICS IN MURINERIF-1 TUMORS

The effects of pentobarbital anesthetic and physical restraint have be en evaluated in murine RIF-1 tumors in terms of their suitability in p roviding minimal temporal variations in core and tumor temperatures, i ntracellular (pH(MR)) and extracellular (pH(F)) tumor pH, and tumor bi oenergetics. pH(F) was measured using a fibreoptic pH probe, The impli cations of the changes in these parameters on the combined studies of in vivo MRS and hyperthermia have been discussed, The temporal variati ons of core and tumor temperatures, pH(F) and pH(MR) between the anest hetised and restrained mice were statistically significant (p <0.0001, p <0.005, and p <0.0001, respectively), Differences in the temperatur es between the two groups varied with time, and were maximum at about 2 h after pentobarbital. In the anesthetised mice, while there was a n et increase of 0.28 pH units in pH,, there was a drop by 0.32 pH units in pH(MR) (p <:0,001), Temporal variations of both pH(F) and pH(MR) i n the restrained mice were relatively constant, In light of these find ings, wherever possible, physical restraint in a suitably designed hol der is suggested for immobilizing animals for magnetic resonance spect roscopy studies, (C) 1997 Elsevier Science Inc.