Motor impairments induced by microinjection of linamarin in the dorsal hippocampus of Wistar rats

Abstract

Introduction: Cassava, also known as yuca or manioc (Manihot esculenta Crantz), is a staple food in tropical and subtropical regions since it is an important source of carbohydrates. Nevertheless, it contains cyanogenic compounds including lotaustralin and linamarin, which have been shown by experimental models to affect brain structures such as the thalamus, the piriform cortex, the hippocampus, and others. These findings may explain the presence of such neurological diseases as konzo and tropical ataxic neuropathy. However, hippocampal involvement in the neurological alterations associated with the chemical compounds in cassava has yet to be explored.

Method: Male Wistar rats (3 months old), were assigned to 4 groups (n = 8 per group) as follows: a vehicle-control group (receiving injectable solution 1μl) and three groups receiving linamarin (10, 15, and 20mM). The substances were microinjected intrahippocampally (CA1) every 24hours for 7 consecutive days, and their effects on locomotor activity, rotarod, and swim tests were assessed daily.

Results: Linamarin microinjected into the dorsal hippocampus produced hyperactivity and loss of motor coordination which became more evident as treatment time increased. In the swim test, rats treated with linamarin displayed lateral rotation beginning on the fourth day of microinjection.

Conclusions: Microinjection of linamarin into the dorsal hippocampus of the rat is associated with impaired motor coordination, suggesting that the dorsal hippocampus, among other brain structures, may be affected by the neurological changes associated with inappropriate consumption of cassava in humans.

Keywords: Cassava; Incoordinación motriz; Konzo; Lateral swimming; Linamarin; Linamarina; Motor impairment; Nado lateral; Neuropatía atáxica tropical; Tropical ataxic neuropathy; Yuca.