Ketamine-induced cell dehydration as a mechanism of it's analgesic and anesthetic effects

Effect of intraperitoneally (i.p.) injected sub-anesthetic (8x10-5-8x10-2 mg/g) and anesthetic (0.125mg/g) doses of ketamine on rats' pain sensitivity and tissue hydration of different organs were studied. determination of water content of tissue was performed by adrian's traditional tissue drying experimental procedure. the number of functionally active receptors were determined by counting the number of [3h]-ouabain in tissues. latent period of pain sensitivity was defined by means of hot plate test. ketamine in sub-anesthetic doses (8x10-5-8x10-2 mg/g i.p.) had depressing effect on rats' latent period of pain sensitivity which was accompanied by dehydration of tissues and decrease of the number of [3h]-ouabain receptors in membrane of tissues of different organs. the ouabain influence on brain cell hydration was characterized by dose dependent (10-9-10-4m) three phases and this fact was accompanied by corresponding changes of number of ouabain receptors in membrane. ketamine anesthetic dose had reversing effect on all three phases of ouabain - induced cell hydration. it was suggested that ketamine - induced cell dehydration leading to decrease of number of functional active proteins in membrane serves as a powerful mechanism through which an analgesic and anesthetic effects of ketamine on organisms were realized.