Functional abnormalities of the motor tract in the rat after portocaval anastomosis and after carbon tetrachloride induction of cirrhosis

• Published in: Metabolic brain disease 2006-12, Vol.21 (4), p.297-308
• Main Authors: ORIA, Marc, RAGUER, Nuria, CHATAURET, Nicolas, BARTOLI, Ramon, ODENA, Gemma, PLANAS, Ramon, CORDOBA, Juan
• Format: Article
• Language: English
• Subjects: Anastomosis, Surgical; Anesthetics, Intravenous - pharmacology; Animals; Biological and medical sciences; Carbon Tetrachloride; Cerebrospinal fluid. Meninges. Spinal cord; Disease Models, Animal; Efferent Pathways - pathology; Efferent Pathways - physiopathology; Evoked Potentials, Motor - drug effects; Hepatic Encephalopathy - chemically induced; Hepatic Encephalopathy - pathology; Hepatic Encephalopathy - physiopathology; Liver Cirrhosis - chemically induced; Liver Cirrhosis - pathology; Liver Cirrhosis - physiopathology; Male; Medical sciences; Nervous system (semeiology, syndromes); Neurology; Neuropharmacology; Neuroprotective agent; Pharmacology. Drug treatments; Portasystemic Shunt, Surgical; Propofol - pharmacology; Pyramidal Tracts - pathology; Pyramidal Tracts - physiopathology; Rats; Rats, Sprague-Dawley; Reaction Time
• ISSN: 0885-7490; 1573-7365
• DOI: 10.1007/s11011-006-9036-z

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