Functional abnormalities of the motor tract in the rat after portocaval anastomosis and after carbon tetrachloride induction of cirrhosis.
BACKGROUND
Hepatic encephalopathy is a neurologic syndrome secondary to liver failure that causes cognitive and motor abnormalities. Impairment in the function of the first neuron of the motor tract (corticospinal tract) has been demonstrated in patients with cirrhosis and minimal hepatic encephalopathy.


OBJECTIVE
Investigate the function of the first neuron of the motor tract in experimental models of minimal hepatic encephalopathy.


METHODS
Rats with portocaval anastomosis (n = 8) and rats with carbon tetrachloride induced cirrhosis (n = 11) underwent neurophysiological recording under light anesthesia with propofol. Motor evoked potentials were elicited applying a transcranial electric pulse and were recorded in the tibialis anterior muscle. The effect of the dose of anesthesia was assessed in a group of normal rats (n = 10).


RESULTS
Rats with portocaval anastomosis exhibited a decrease in motor evoked potentials amplitude following surgery (67 +/- 11 to 41 +/- 16%, P < 0.001). Cirrhotic rats exhibited an increase in motor evoked potentials latency after the appearance of ascites (4.65 +/- 0.43 to 5.15 +/- 0.67 ms., P = 0.04). Increasing doses of propofol produced a decrease in the amplitude and an increase in the latency of motor evoked potentials.


CONCLUSIONS
It is possible to reproduce functional abnormalities of the central motor tract in rats with portocaval anastomosis and carbon tetrachloride induced cirrhosis. The development of motor abnormalities in experimental models of minimal hepatic encephalopathy offers the possibility to investigate the mechanisms involved in the pathogenesis of hepatic encephalopathy and test therapeutic strategies.
Oria
Marc
M
Liver Unit, Hospital Universitari Vall d'Hebron, Department of Medicine, Universitat Autònoma de Barcelona, Passeig Vall d'Hebron 119-129, 08035, Barcelona, Spain.
Raguer
Nuria
N
Chatauret
Nicolas
N
Bartolí
Ramón
R
Odena
Gemma
G
Planas
Ramón
R
Córdoba
Juan
J
D000714:Anastomosis, Surgical; D018686:Anesthetics, Intravenous / Q000494:pharmacology; D000818:Animals; D002251:Carbon Tetrachloride; D004195:Disease Models, Animal; D004525:Efferent Pathways / Q000473:pathology / Q000503:physiopathology; D019054:Evoked Potentials, Motor / Q000187:drug effects; D006501:Hepatic Encephalopathy / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000473:pathology / Q000503:physiopathology*; D008297:Male; D011170:Portasystemic Shunt, Surgical; D015742:Propofol / Q000494:pharmacology; D011712:Pyramidal Tracts / Q000473:pathology / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time
D018686:Anesthetics, Intravenous; D002251:Carbon Tetrachloride; D015742:Propofol