Chlorpyrifos impaired cerebellar oxidative and cholinesterase activities in rats: Mitigating efficacy of Nigella sativa Oil

Background: Motor dysfunctions are some of the characteristic symptoms of organophosphate (OP) poisoning and they have been associated with decreased levels of cholinesterase inhibition within motor areas of the brain. Objectives: The current study aims to investigate the potential neuroprotective effects of Nigella sativa oil (NSO) in alleviating chlorpyrifos (CPF) induced toxicity in the cerebella and motor cortices of the rat brains using combined behavioural, biochemical and histochemical methods. Methods: Thirty-two rats were randomly divided into four groups (eight rats per group), exposed to 1ml/kg of normal saline, 14.9 mg/kg of CPF, 14.9 mg/kg of CPF plus 1ml/kg of NSO and 1ml/kg of NSO respectively for 14 consecutive days. The rats were each exposed to a single trial of the Open Field Test (OFT) on day 13 of the experiment. This experimental test measured locomotor activity levels (line crossing frequency (LCF)) and exploratory (rearing frequency (RF)) activities in the rats studied. The rats were euthanized on day 15 of the experiment and the brains were subsequently excised. The cerebella cortices of five brains were removed and homogenised to analyse for total reactive oxygen species (ROS), nitric oxide (NO) levels and acetylcholinesterase (AChE) activity. The motor and cerebella cortices from three other brains in each group were processed for histology (Nissl stain) and proliferative activity (Ki67 immunohistochemistry). Results: Rats exposed to CPF experienced a significant increase in cerebella NO and ROS levels, depletion in AChE activity, neurogenic cells loss and subsequent reduction in locomotor and exploratory behaviours respectively (LCF and RF). However, interventional treatment with NSO depleted markers of oxidative damage (NO and ROS), reduced AChE inhibition, preserved neurogenic (Ki67) cells distribution and motor functions. Conclusion: These results demonstrate the potential efficacy of NSO in OP poisoning and the roles of neurogenic and oxidative functions in the pathophysiology and treatment of motor dysfunction in OP neurotoxicity.

Neuroprotective potential of Cilostazol in 3-NP provoked Huntington's disease-associated symptoms

Huntington's disease (HD), a neurodegenerative condition specified by mitochondrial deficits, psychiatric and cognitive impairment developed due to neuronal damage in the brain. 3-nitropropionic acid (3-NP), an inhibitor of succinate dehydrogenase develops behavioral, biochemical as well as histological alterations in the striatal region of brain, which resembles HD in humans. Phosphodiesterases (PDEs) participate in cognition, motor functions, and behavior as well as also offers neuroprotection. The present investigation was framed to analyze the neuro-defensive characteristics of cilostazol PDE3 inhibitor over the 3-NP induced behavioral, striatal and mitochondrial deficits. Administration of 3-NP (10mg kg-1; i.p.) for the duration of 14 days has shown considerable alterations in behavior such as decreased locomotion (actophotometer), reduced grip strength (rota-rod test), spatial learning memory (elevated plus maze and Morris water maze). In parallel to, 3-NP treated rats exhibit biochemical changes such as increased oxidative stress (enhanced lipid peroxides, reduced glutathione, catalase, and superoxide dismutase), disturbed cholinergic function (increased acetylcholinesterase activity), increased inflammation (more myeloperoxidase) and mitochondrial dysfunction (reduced complex I, II and IV activity). Histopathological changes (Nissl stain) like chronic neuronal gap, pyknotic nuclei as well as injured cells in the cerebral cortex and hippocampus were also observed in 3-NP treated rats. Administration of cilostazol considerably restored behavioral abnormalities, biochemical and histopathological alterations. In this investigation, cilostazol offered neurodefensive effects which were established by behavioral and biochemical paradigms, which confirmed the potent neurodefensive aspect of cilostazol in 3-NP provoked behavioral and biochemical abnormalities.

Dr. V. V. Muravyov. Nerve cell in normal and pathological state (Russian archive of pathology, clinical medical and bacteriology. 1898, December)

Dr. Muraviev examines the structural features of the nerve cell in its normal and pathological state, using the Nissl stain. According to the author, our knowledge of the structure of the cell in the normal state can currently serve as the basis for pathological observations.

Physiological and anatomical investigation of the auditory brainstem in the Fat-tailed dunnart (Sminthopsis crassicaudata)

The fat-tailed dunnart (Sminthopsis crassicaudata) is a small (10–20 g) native marsupial endemic to the south west of Western Australia. Currently little is known about the auditory capabilities of the dunnart, and of marsupials in general. Consequently, this study sought to investigate several electrophysiological and anatomical properties of the dunnart auditory system. Auditory brainstem responses (ABR) were recorded to brief (5 ms) tone pips at a range of frequencies (4–47.5 kHz) and intensities to determine auditory brainstem thresholds. The dunnart ABR displayed multiple distinct peaks at all test frequencies, similar to other mammalian species. ABR showed the dunnart is most sensitive to higher frequencies increasing up to 47.5 kHz. Morphological observations (Nissl stain) revealed that the auditory structures thought to contribute to the first peaks of the ABR were all distinguishable in the dunnart. Structures identified include the dorsal and ventral subdivisions of the cochlear nucleus, including a cochlear nerve root nucleus as well as several distinct nuclei in the superior olivary complex, such as the medial nucleus of the trapezoid body, lateral superior olive and medial superior olive. This study is the first to show functional and anatomical aspects of the lower part of the auditory system in the Fat-tailed dunnart.

Physiological and anatomical investigation of the auditory brainstem in the Fat-tailed Dunnart (Sminthopsis crassicaudata)

The fat-tailed Dunnart (Sminthopsis crassicaudata) is a small (10-20g) native marsupial endemic to the south west of Western Australia. Currently little is known about the auditory capabilities of the dunnart, and of marsupials in general. Consequently, this study sought to investigate several electrophysiological and anatomical properties of the dunnart auditory system. Auditory brainstem responses (ABR) were recorded to brief (5ms) tone pips at a range of frequencies (4-47.5 kHz) and intensities to determine auditory brainstem thresholds. The dunnart ABR displayed multiple distinct peaks at all test frequencies, similar to other mammalian species. ABR showed the dunnart is most sensitive to higher frequencies increasing up to 47.5 kHz. Morphological observations (Nissl stain) revealed that the auditory structures thought to contribute to the first peaks of the ABR were all distinguishable in the dunnart. Structures identified include the dorsal and ventral subdivisions of the cochlear nucleus, including a cochlear nerve root nucleus as well as several distinct nuclei in the superior olivary complex, such as the medial nucleus of the trapezoid body, lateral superior olive and medial superior olive. This study is the first to show functional and anatomical aspects of the lower part of the auditory system in the Fat-tailed Dunnart.

Physiological and anatomical investigation of the auditory brainstem in the Fat-tailed Dunnart (Sminthopsis crassicaudata)

The fat-tailed Dunnart (Sminthopsis crassicaudata) is a small (10-20g) native marsupial endemic to the south west of Western Australia. Currently little is known about the auditory capabilities of the dunnart, and of marsupials in general. Consequently, this study sought to investigate several electrophysiological and anatomical properties of the dunnart auditory system. Auditory brainstem responses (ABR) were recorded to brief (5ms) tone pips at a range of frequencies (4-47.5 kHz) and intensities to determine auditory brainstem thresholds. The dunnart ABR displayed multiple distinct peaks at all test frequencies, similar to other mammalian species. ABR showed the dunnart is most sensitive to higher frequencies increasing up to 47.5 kHz. Morphological observations (Nissl stain) revealed that the auditory structures thought to contribute to the first peaks of the ABR were all distinguishable in the dunnart. Structures identified include the dorsal and ventral subdivisions of the cochlear nucleus, including a cochlear nerve root nucleus as well as several distinct nuclei in the superior olivary complex, such as the medial nucleus of the trapezoid body, lateral superior olive and medial superior olive. This study is the first to show functional and anatomical aspects of the lower part of the auditory system in the Fat-tailed Dunnart.

Histological studies on the retina and cerebellum of Wistar rats treated with Arteether™

Introduction: Arteether™, a derivative of artemisinin, is among the recent drugs that have given renewed hope for combating malarial menace. The present study investigated the effects of arteether™ on the histology of the retina and cerebellum of Wistar rats. Materials and Methods: Twenty adult albino Wistar rats weighing 150-200 g, were randomly divided into four groups (A, B, C and D) of five animals each and used for this study. Group A rats were given intramuscular (i.m.) arteether™ (3 mg/kg b.w.) daily for 3 days. Group B rats were given i.m. arteether™ (6 mg/kg b.w.) daily for 3 days. Group C rats were also given i. m. of arteether™ (3 mg/kg b. w.) daily for 3 days, and the same dose was repeated at two-weekly intervals for 4 further weeks; while Group D rats which received normal saline (0.9 % w/v, 3 ml/kg b.w.), served as controls. At the end of the experiment, the rats were sacrificed by cervical dislocation. The retina and cerebellum were excised and processed routinely for histopathology changes, using haematoxylin and eosin stain (H & E), as well as Nissl stain. Results: Results obtained showed normal cellular components of the retina and cerebellum in all groups, and no cyto-pathological changes were observed. Conclusion: Thus, this study showed that under light microscopic examination, therapeutic doses of arteether™ caused no significant cyto-pathologic changes in the retina and cerebellum of Wistar rats.