Associative learning deficit in two experimental models of hepatic encephalopathy.
People with hepatic insufficiency can develop hepatic encephalopathy (HE), a complex neuropsychological syndrome covering a wide range of neurological and cognitive and motor alterations. The cognitive deficits include disturbances in intellectual functions such as memory and learning. In spite of its high prevalence in western societies, the causes of HE have not yet been clearly established. For this reason, experimental models of HE are used to study this condition. In this work, two experimental models were used, one Type B HE (portacaval shunt) and the other Type C HE (cirrhosis by intoxication with thioacetamide), to evaluate its effect on two tasks of associative learning: two-way active avoidance and step-through passive avoidance. The results show an impediment both in acquisition and retention of active avoidance in both models of HE. However, in passive avoidance, only the rats with portacaval shunt presented a memory deficit for the aversive event. In our opinion, these results can be explained by alterations in the neurotransmission system presented by animals with hepatic insufficiency, which are mainly caused by a rise in cerebral histamine and a dysfunction of the glutamatergic system.
Méndez
Marta
M
Laboratorio de Neurociencias, Departamento de Psicología, Universidad de Oviedo, Plaza Feijoo s/n, 33003 Oviedo, Spain.
Méndez-López
Magdalena
M
López
Laudino
L
Aller
María Angeles
MA
Arias
Jaime
J
Arias
Jorge L
JL
D000818:Animals; D001245:Association Learning; D001362:Avoidance Learning; D003071:Cognition; D004195:Disease Models, Animal; D006501:Hepatic Encephalopathy / Q000209:etiology* / Q000503:physiopathology / Q000523:psychology*; D008103:Liver Cirrhosis / Q000150:complications / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008568:Memory; D011167:Portacaval Shunt, Surgical / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D013853:Thioacetamide / Q000008:administration & dosage / Q000633:toxicity
D013853:Thioacetamide