Long–term spatial memory and morphological changes in hippocampus of Wistar rats exposed to smoke from Carica papaya leaves

ABSTRACTObjectiveTo investigate the effects of smoking of dried leaves of Carica papaya (pawpaw) based on ethnopharmacological information which indicated that smoking of papaya leaves could influence motor performance and learning.MethodsTwenty-four rats were used for the study, and were grouped into four groups. Groups 1 served as the control (not exposed to papaya leaves smoke), while Groups 2, 3 and 4 were exposed to smoke from 6.25 g, 12.50 g and 18.75 g of dry pawpaw leaves respectively in a smoking chamber twice daily for 21 d with each exposure lasting for 3 min. Lastly, hippocampus was harvested in each group for histological study.ResultsThe results showed that there were significant (P<0.05) increases in mean of recall latencies of long-term spatial memory in the animal administered the high dose while the other groups had significantly (P<0.05) lower frequencies. Histological investigation showed signs of mild neural degeneration in high dose group and hypochromic appearance of the Nissl substance in all treated groups.ConclusionsIn conclusion, the findings from this study has demonstrated that smoking of papaya leaves has the ability to maintain an intact long-term spatial memory at all doses but retrieving such memory is faster with the low and medium dosages

Selenium reduces nociceptive response in acute 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced neurotoxicity

The potential of Se to alleviate pain associated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity was investigated. Swiss mice were injected with MPTP (20 mg/kg) 4 times with an interval of 2 h in 1 day. Seven days after MPTP injection, the mice (n = 5 mice per group) were randomly assigned to groups: MPTP-, DOPA (50 mg/kg)-, Se4 (0.4 mg/kg)-, Se6 (0.6 mg/kg)-, DOPA+Se4-, and DOPA+Se6-treated groups were compared with controls. MPTP mice were treated for seven days; thereafter, motor-coordination and nociceptive-motor reactions were assessed. Pro-inflammatory cytokines (IL-1β, IL-6 and TNFα), and selected pain biomarkers (substance P (SP), glutamate and β-endorphin) were assessed in the serum and the substantial nigra pars compacta (SNpc). Motor activity was increased slightly by Se (0.6 or 0.4 mg/kg) . MPTP (10.48 ± 2.71 or 11.81 ± 1.28 s . 3.53 ± 0.06 s respectively) but considerably increased by DOPA (50 mg/kg) . MPTP (50.47 ± 3.06 s . 3.53 ± 0.06 s respectively). Se and DOPA increased nociceptive threshold but Se alone reduced both serum and SN pro-inflammatory cytokines. Se modulates SP while DOPA modulates SP and glutamate in the SNpc of mice treated with MPTP. Se suppressed pro-inflammatory cytokines and restored the basal pain biomarkers in the SNpc of mice treated with MPTP. Se requires further study as analgesic adjuvant

Effect of Cnidoscolous aconitifolius (Miller) I.M. Johnston leaf extract on reproductive hormones of female rats

Background: The increase in the rate of infertility in women has prompted the need to search for plants with antifertility potentials. Objective: The effect of administration of aqueous extract of Cnidoscolous aconitifolius leaves for seven days on reproductive hormones of female Wistar rats was investigated. Materials and Methods: Sixty female albino rats were grouped into four (A, B, C and D) of 15 each. Group A (the control) received orally 6.5 ml kg-1 body weight of distilled water on daily basis for 7 days. Groups B, C and D were treated like the control except that they received 250, 500 and 1000 mg kg-1 body weight of the extract. Results: Phytochemical screening of the extract revealed the presence of alkaloids, saponins, phenolics, tannins, flavonoids, anthraquinones, phlobatannins and triterpenes. Administration of the extract produced significant increase (p<0.05) in the serum prolactin concentration whereas those of estradiol, progesterone, follicle stimulating and luteinizing hormones were significantly reduced. Conclusion: The alterations in the female rat reproductive hormones by the extract are indications of adverse effect on the maturation and ovulation of follicles. Consequently, the extract may impair fertility and conception in female rats. Thus, the Cnidoscolous aconitifolius leaf extract may be explored as a female contraceptive