Regional catecholamine concentrations in brain and spinal cord of male albino rats treated with the synthetic pyrethroid cyfluthrine

Abstract

The principal objective of this study was to determine the modifications induced by the synthetic pyrethroid insecticide cyfluthrin in the concentrations of dopamine (DA), norepinephrine (NE) and epinephrine(E) in selected brain and spinal cord regions of male albino rats. A group of 30 rats were injected intraperitoneally every other day with cyfluthrin at 1/4 LD50 dose level for 18 days. Other two groups (30 rats each) were daily given cyfluthrin intraperitoneally at the dose levels of 1/8 LD50 and 1/50 LD50 for 18 days and 6 weeks respectively. All treated animals developed a time and dose dependent toxicity symptoms and behavioural changes representing the typical CS syndromes produced by a- cyano pyrethroids . These involve skin paresthesia , body tremor , motor incoordination , choreoathetotic writhing and profuse salivation . Clonic and tonic seizures appeared at the terminal stages . Concentrations of DA, NE and E were measured in the olfactory bulb, hypothalamus, cerebellum, medulla oblongata, thoracic and lumbar regions of the spinal cord homogenates of rats treated for 3, 6, 9, 12, 15 or 18 days every other day or daily with 1/4 or 1/8 LD50 dose levels respectively and of rats treated daily for 1, 2, 3, 4, 5 or 6 weeks with 1/50 LD50 dose level. It was found that cyfluthrin at all dose levels used induced a general increase of DA, NE and E in all studied brain and spinal cord regions. The pattern of this increase was both time and regional dependent. These data suggest that cyfluthrin is a mammalian neurotoxic agent, and the severity of its toxic action is dependent on the treatment period as well as the affected region of the central nervous system.