TY - JOUR
T1 - Effect of traumatic injury on membrane phosphatase activity in cat spinal cord
AU - Goldman, Stephen S.
AU - Elowitz, Eric
AU - Flamm, Eugene S.
N1 - Funding Information:
Abbreviations; pNPPase-p-nitrophenylphosphatase, DTT-dithiothreitol. ’ These studies were supported by grant NS10164 from the National Institutes of Health. The authors thank Dr. V. DeCrescito and Dr. J. Tomasula for the surgical preparations and Mrs. J. Grana for typing the manuscript.
PY - 1983/12
Y1 - 1983/12
N2 - The enzymatic activities of the spinal cord membrane phosphatases, (Na,K)ATPase, KpNPPase, 5′-nucleotidase, MgATPase, and MgpNPPase, were determined following contusion injury. Within 30 min after injury, the activities of (Na,K)ATPase, KpNPPase, and 5′-nucleotidase were suppressed at the injury site and remained suppressed for 24 h. Considerable loss of (Na,K)ATPase and KpNPPase activity was seen along the longitudinal axis of the spinal cord for the first 4 h after injury, whereas at 24 h after injury, there was almost complete restitution in the activity of those enzymes. No similar changes in activity were observed for the MgATPase, whereas the activity of the MgpNPPase progressively worsened with time at the injury site. The deduce the pathobiochemical process that accounts for the loss of spinal membrane phosphatase activity, spinal cord membranes were incubated in vitro in the presence of a superoxide anion-generating system, as well as in the presence of trypsin and lysolecithin. It was found that superoxide anions inhibited only the activity of transport phosphatase, KpNPPase, whereas trypsin inhibited the activity of both KpNPPase and MgpNPPase. No inhibition of 5′-nucleotidase was observed by superoxide anions; however, the activity of 5′-nucleotidase was enhanced by trypsin, lysolecithin, or both in concert. These results suggest that the pathobiochemical process that accounts for the loss of spinal membrane phosphatase activity that follows injury can be attributed to the concerted effects of free radical attack as well as the activation of proteolytic and lipolytic enzymes. Inactivation of spinal membrane phosphatase can occur by direct attack of these processes on the membrane or by loss of membrane material, e.g., solubilization.
AB - The enzymatic activities of the spinal cord membrane phosphatases, (Na,K)ATPase, KpNPPase, 5′-nucleotidase, MgATPase, and MgpNPPase, were determined following contusion injury. Within 30 min after injury, the activities of (Na,K)ATPase, KpNPPase, and 5′-nucleotidase were suppressed at the injury site and remained suppressed for 24 h. Considerable loss of (Na,K)ATPase and KpNPPase activity was seen along the longitudinal axis of the spinal cord for the first 4 h after injury, whereas at 24 h after injury, there was almost complete restitution in the activity of those enzymes. No similar changes in activity were observed for the MgATPase, whereas the activity of the MgpNPPase progressively worsened with time at the injury site. The deduce the pathobiochemical process that accounts for the loss of spinal membrane phosphatase activity, spinal cord membranes were incubated in vitro in the presence of a superoxide anion-generating system, as well as in the presence of trypsin and lysolecithin. It was found that superoxide anions inhibited only the activity of transport phosphatase, KpNPPase, whereas trypsin inhibited the activity of both KpNPPase and MgpNPPase. No inhibition of 5′-nucleotidase was observed by superoxide anions; however, the activity of 5′-nucleotidase was enhanced by trypsin, lysolecithin, or both in concert. These results suggest that the pathobiochemical process that accounts for the loss of spinal membrane phosphatase activity that follows injury can be attributed to the concerted effects of free radical attack as well as the activation of proteolytic and lipolytic enzymes. Inactivation of spinal membrane phosphatase can occur by direct attack of these processes on the membrane or by loss of membrane material, e.g., solubilization.
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U2 - 10.1016/0014-4886(83)90087-0
DO - 10.1016/0014-4886(83)90087-0
M3 - Article
C2 - 6317425
AN - SCOPUS:0021068509
SN - 0014-4886
VL - 82
SP - 650
EP - 662
JO - Experimental Neurology
JF - Experimental Neurology
IS - 3
ER -