Hypothalamus - Response to early paracetamol exposure in male rats offspring.

One of the reasons for using paracetamol during pregnancy is fever. The brain structure responsible for maintaining proper body temperature, but also for controlling some endocrine aspects is hypothalamus. In this study we examined the effect of early pretreatment of paracetamol on hypothalamic neurotransmission in rats' offspring. We used two-month old rats previously exposed to paracetamol at doses of 5 (P5) and 15 mg/kg (P15) during gestational development and next postnatally. The concentration of monoamines, their metabolites and amino acids in hypothalamus was chromatographically determined. The results of biochemical analysis were compared with the Control animals (Con). We found differences between groups in the concentration of main noradrenaline metabolite in hypothalamus. The control group had significantly higher level of 3-methoxy-4-hydroxyphenylglycol (MHPG) compared with rats exposed to paracetamol (F(2,27) = 7.96, p < 0.005). Simultaneously the level of dopamine (DA) (F(2,27) = 4.33, p < 0.05) and its metabolite - homovanillic acid (HVA) (F(2,27) = 17.03, p < 0.005) was increased in the hypothalamus of animals treated with lower dose of the drug. Biochemical analyses show an increase in 3,4-dihydroxyphenyl acetic acid (DOPAC) concentration in P5 group compared to the control rats and group treated with higher dose of paracetamol (F(2,27) = 7.37, p < 0.005). In the hypothalamus significant decrease of glutamic acid concentration was also observed in the group treated with paracetamol at dose of 5 mg. These results demonstrated that paracetamol had a significant effect on dopaminergic and noradrenergic neurotransmission and changed the concentration of glutamic acid in hypothalamus - heat-regulating center and important element of hypothalamic-pituitary- gonadal axis.

Early paracetamol exposure decreases brain-derived neurotrophic factor (BDNF) in striatum and affects social behaviour and exploration in rats.

The biochemical and behavioral responses to prenatal and early postnatal exposure to paracetamol in rats are not well understood. The effect of daily maternal and early life administration of 5 mg/kg (group P5) or 15 mg/kg paracetamol (group P15) was evaluated in two-month old male rats, relative to control animals receiving tap water (Con). Social behavior and episodic memory were investigated with Social Interaction and Novel Object Recognition (NOR) tests. Quantification of brain-derived neurotrophic factor (BDNF) was determined in prefrontal cortex, hippocampus and striatum using enzyme-linked immunosorbent assay (ELISA). Control animals exhibited a higher total frequency of social interactions and greater frequency of sniffing compared to rats exposed to paracetamol, and we found a statistically significant increase in the occurrence of pinning in paracetamol-treated animals. Rats from the 15 mg/kg group exhibited a greater interest in objects in the NOR test and spent more time exploring objects during the familiarization and choice phases. Biochemical analysis showed significant differences in striatal BDNF between the groups, specifically, a nearly two-fold decrease in striatal BDNF in the paracetamol groups (P5: 6.78 ±â€¯0.60 pg/mg; P15: 6.06 ±â€¯0.46 pg/mg) relative to the control group (Con: 11.33 ±â€¯2.00 pg/mg). These results indicate that paracetamol exposure induces changes in social behaviour and exploration in rats and results in a significant decrease of striatal BDNF.

Paracetamol - Effect of early exposure on neurotransmission, spatial memory and motor performance in rats.

In the present study we examined the effect of prenatal and early life paracetamol exposure on neurotransmission and its behavioural manifestation in rat male pups. In order to assess the ability of spatial learning and memory consolidation and the level of physical and exploratory activity we conducted a series of behavioural tests: Staircase Test, Hole Board Test and Water Maze. The concentrations of monoamines, metabolites and amino acids were determined using High Performance Liquid Chromatography in the prefrontal cortex, hippocampus and striatum. The effect on spatial memory and exploratory behaviour was most pronounced in animals treated with the lower dose of paracetamol. In this group we have observed a much lower motor activity and decreased head-dipping behaviour. Simultaneously, the number of crossings in the Water Maze under the previous platform position during the probe trial was significantly higher in rats treated with paracetamol at the dose of 5mg/kg. There was also a preference for a new location of a platform to the original position of the platform in the reversal probe trial of this group. These results indicate that early paracetamol exposure produces major changes in serotonergic and dopaminergic neurotransmission in the prefrontal cortex and striatum. At the same time, administration of the drug in early life results in the spectacular change in the amino acid level, in particular in the hippocampus and cortex. This has been reflected in the behaviour of animals in the Water Maze and Hole Board Test (without any noticeable impact on the Staircase Test).

Cerebellar level of neurotransmitters in rats exposed to paracetamol during development.

BACKGROUND: The present study was designed to clarify the effect of prenatal and postnatal paracetamol administration on the neurotransmitter level and balance of amino acids in the cerebellum. METHODS: Biochemical analysis to determine the concentration of neurotransmitters in this brain structure was performed on two-month-old Wistar male rats previously exposed to paracetamol in doses of 5 (P5, n=10) or 15mg/kg (P15, n=10) throughout the entire prenatal period, lactation and until the completion of the second month of life, when the experiment was terminated. Control animals were given tapped water (Con, n=10). The cerebellar concentration of monoamines, their metabolites and amino acids were assayed using High Performance Liquid Chromatography (HPLC). RESULTS: The present experiment demonstrates that prenatal and postnatal paracetamol exposure results in modulation of cerebellar neurotransmission with changes concerning mainly 5-HIAA and MHPG levels. CONCLUSION: The effect of paracetamol on monoaminergic neurotransmission in the cerebellum is reflected by changes in the level of catabolic end-products of serotonin (5-HIAA) and noradrenaline (MHPG) degradation. Further work is required to define the mechanism of action and impact of prenatal and postnatal exposure to paracetamol in the cerebellum and other structures of the central nervous system (CNS).

Passiflora incarnata L. Improves Spatial Memory, Reduces Stress, and Affects Neurotransmission in Rats.

Passiflora incarnata L. has been used as a medicinal plant in South America and Europe since the 16th century. Previous pharmacological studies focused mainly on the plant's sedative, anxiolytic, and anticonvulsant effects on the central nervous system and its supporting role in the treatment of addiction. The aim of the present study was to evaluate the behavioral and neurochemical effects of long-term oral administration of P. incarnata. The passionflower extract (30, 100, or 300 mg/kg body weight/day) was given to 4-week-old male Wistar rats via their drinking water. Tests were conducted after 7 weeks of treatment. Spatial memory was assessed in a water maze, and the levels of amino acids, monoamines, and their metabolites were evaluated in select brain regions by high performance liquid chromatography (HPLC). We observed reduced anxiety and dose-dependent improvement of memory in rats given passionflower compared to the control group. In addition, hippocampal glutamic acid and cortical serotonin content were depleted, with increased levels of metabolites and increased turnover. Thus, our results partially confirmed the proposed mechanism of action of P. incarnata involving GABAA receptors. Copyright © 2016 John Wiley & Sons, Ltd.