Biomedical subjects

Dinesh Dhingra

Publications and source records attributed to Dinesh Dhingra.

7 recordsLinked to original sources

PubMed2006

Antidepressant-like activity of Glycyrrhiza glabra L. in mouse models of immobility tests.

The present study was undertaken to investigate the effects of aqueous extract of Glycyrrhiza glabra L. (Family: Fabaceae), popularly known as liquorice, on depression in mice using forced swim test (FST) and tail suspension test (TST). The extract of G. glabra (75, 150, and 300 mg/kg) was administered orally for 7 successive days in separate groups of Swiss young male albino mice. The dose of 150 mg/kg of the extract significantly reduced the immobility times of mice in both FST and TST, without any significant effect on locomotor activity of mice. The efficacy of extract was found to be comparable to that of imipramine (15 mg/kg i.p.) and fluoxetine (20 mg/kg i.p.). Liquorice extract reversed reserpine-induced extension of immobility period of mice in FST and TST. Sulpiride (50 mg/kg i.p.; a selective D2 receptor antagonist) and prazosin (62.5 microg/kg i.p.; an alpha1-adrenoceptor antagonist) significantly attenuated the extract-induced antidepressant-like effect in TST. On the other hand, p-chlorophenylalanine (100 mg/kg i.p.; an inhibitor of serotonin synthesis) did not reverse antidepressant-like effect of liquorice extract. This suggests that antidepressant-like effect of liquorice extract seems to be mediated by increase of brain norepinephrine and dopamine, but not by increase of serotonin. Monoamine oxidase inhibiting effect of liquorice may be contributing favorably to the antidepressant-like activity. Thus, it is concluded that liquorice extract may possess an antidepressant-like effect.

Analysis of Variance↗

PubMed2006

Comparative brain cholinesterase-inhibiting activity of Glycyrrhiza glabra, Myristica fragrans, ascorbic acid, and metrifonate in mice.

The central cholinergic pathways play a prominent role in the learning and memory processes. Acetylcholinesterase is an enzyme that inactivates acetylcholine. The present study was undertaken to estimate the acetylcholinesterase- inhibiting activity of extracts of Glycyrrhiza glabra, Myristica fragrans seeds, and ascorbic acid and compare these values with a standard acetylcholinesterase-inhibiting drug, metrifonate. Aqueous extract of G. glabra (150 mg/kg p.o. for 7 successive days), n-hexane extract of M. fragrans seeds (5 mg/kg p.o. for 3 successive days), ascorbic acid (60 mg/kg i.p. for 3 successive days), and metrifonate (50 mg/kg i.p.) were administered to young male Swiss albino mice. Acetylcholinesterase enzyme was estimated in brains of mice. G. glabra, M. fragrans, ascorbic acid, and metrifonate significantly decreased acetylcholinesterase activity as compared with their respective vehicle-treated control groups.

Acetylcholinesterase↗

PubMed2006

Antidepressant-like activity of n-hexane extract of nutmeg (Myristica fragrans) seeds in mice.

The present study was undertaken to investigate the effect of an n-hexane extract of Myristica fragrans seeds on depression in mice by using the forced swim test (FST) and the tail suspension test (TST). M. fragrans extract (5, 10, and 20 mg/kg) was administered orally for 3 successive days to different groups of Swiss male young albino mice. M. fragrans extract significantly decreased immobility periods of mice in both the FST and the TST. The 10 mg/kg dose was found to be most potent, as indicated by the greatest decrease in the immobility period compared with the control. Furthermore, this dose of the extract was found to have comparable potency to imipramine (15 mg/kg i.p.) and fluoxetine (20 mg/kg i.p.). The extract did not have a significant effect on locomotor activity of mice. Prazosin (62.5 microg/kg i.p.; an alpha (1)-adrenoceptor antagonist), sulpiride (50 mg/kg i.p.; a selective D(2) receptor antagonist), and p-chlorophenylalanine (100 mg/kg i.p.; an inhibitor of serotonin synthesis) significantly attenuated the M. fragrans extract-induced antidepressant-like effect in the TST. Thus, extract of M. fragrans elicited a significant antidepressant-like effect in mice, when assessed in both the TST and the FST. The antidepressant-like effect of the extract seems to be mediated by interaction with the adrenergic, dopaminergic, and serotonergic systems.

Adrenergic alpha-Antagonists↗

PubMed2004

Memory enhancing activity of Glycyrrhiza glabra in mice.

In the traditional system of medicine, the roots and rhizomes of Glycyrrhiza glabra (family: Leguminosae) have been employed clinically for centuries for their anti-inflammatory, antiulcer, expectorant, antimicrobial and anxiolytic activities. The present study was undertaken to investigate the effects of Glycyrrhiza glabra (popularly known as liquorice) on learning and memory in mice. Elevated plus-maze and passive avoidance paradigm were employed to test learning and memory. Three doses (75, 150 and 300 mg/kg p.o.) of aqueous extract of Glycyrrhiza glabra were administered for 7 successive days in separate groups of animals. The dose of 150 mg/kg of the aqueous extract of liquorice significantly improved learning and memory of mice. Furthermore, this dose significantly reversed the amnesia induced by diazepam (1 mg/kg i.p.) and scopolamine (0.4 mg/kg i.p.). Anti-inflammatory and antioxidant properties of liquorice may be contributing favorably to the memory enhancement effect. Since scopolamine-induced amnesia was reversed by liquorice, it is possible that the beneficial effect on learning and memory was due to facilitation of cholinergic-transmission in mouse brain. However, further studies are necessitated to identify the exact mechanism of action. In the present investigation, Glycyrrhiza glabra has shown promise as a memory enhancing agent in all the laboratory models employed.

Administration, Oral↗

PubMed2004

Improvement of mouse memory by Myristica fragrans seeds.

Memory is one of the most complex functions of the brain and involves multiple neural pathways and neurotransmitter systems. The present study was undertaken to investigate the effect of Myristica fragrans (MF) seeds on learning and memory in mice. The n-hexane extract of MF was administered orally in three doses (5, 10, and 20 mg/kg p.o.) for 3 successive days to different groups of young and aged mice. The learning and memory parameters were assessed using elevated plus-maze and passive-avoidance apparatus. The effect of MF extract on scopolamine (0.4 mg/kg i.p.)- and diazepam (1 mg/kg i.p.)-induced impairment in learning and memory was also studied. MF extract at the lowest dose of 5 mg/kg p.o. administered for 3 successive days significantly improved learning and memory of young and aged mice. This extract also reversed scopolamine- and diazepam-induced impairment in learning and memory of young mice. MF extract enhanced learning and retention capacities of both young and aged mice. The exact mechanism of the memory-improving effect of MF extract was not explored in the present study. But, the observed memory-enhancing effect may be attributed to a variety of properties (individually or in combination) the plant is reported to possess, such as antioxidant, anti-inflammatory, or perhaps procholinergic activity.

Animals↗

PubMed2004

Memory-strengthening activity of Glycyrrhiza glabra in exteroceptive and interoceptive behavioral models.

In the traditional system of medicine, the roots and rhizomes of Glycyrrhiza glabra have been employed clinically for centuries for their anti-inflammatory, anti-ulcer, expectorant, antimicrobial, and anxiolytic activities. The present study was undertaken to investigate the effects of G. glabra, popularly known as liquorice (Mulathi), on learning and memory. The elevated plus-maze and passive avoidance paradigm were employed to evaluate learning and memory parameters. Three doses (75, 150, and 300 mg/kg p.o.) of aqueous extract of G. glabra were administered for 7 successive days in separate groups of mice. The dose of 150 mg/kg of the aqueous extract of liquorice significantly improved learning and memory of mice. Furthermore, this dose reversed the amnesia induced by diazepam (1 mg/kg i.p.), scopolamine (0.4 mg/kg i.p.), and ethanol (1 g/kg i.p.). Anti-inflammatory and antioxidant properties of liquorice may be contributing favorably to the memory enhancement effect. Since scopolamine-induced amnesia was reversed by liquorice, it is possible that the beneficial effect on learning and memory may be because of facilitation of cholinergic transmission in brain. However, further studies are necessitated to identify the exact mechanism of action. In the present investigation, G. glabra has shown promise as a memory enhancer in both exteroceptive and interoceptive behavioral models of memory.

Administration, Oral↗

PubMed2003

Ascorbic Acid: a promising memory-enhancer in mice.

Alzheimer's disease is a progressive neurodegenerative disorder characterized by a gradual decline in memory. The occurrence of Alzheimer's disease is commonplace among the Asian population, particularly among senior citizens. The present study was undertaken to assess the potential of ascorbic acid as a memory-enhancer. Swiss mice of either sex were employed in the present investigation. Elevated plus-maze and passive-avoidance apparatus served as the exteroceptive behavioral models, and diazepam-, scopolamine-, and aging-induced amnesia served as the interoceptive behavioral models. Ascorbic acid (60, 120 mg/kg) injected for 3 and 8 consecutive days improved learning and memory of aged mice as indicated by decreased transfer-latency and increased step-down latency. Furthermore, ascorbic acid provided protection to the young animals from scopolamine- and diazepam-induced impairment of memory. Ascorbic acid was found to be more potent than piracetam as reflected by the smaller dose, more pronounced effect, and quicker onset of action. Ascorbic acid has shown promise as a powerful memory-improving agent particularly effective in aged animals. Hence, ascorbic acid might prove to be a useful memory-restorative agent in the treatment of dementia seen in elderly individuals. The underlying mechanism of action of ascorbic acid may be attributed to its antioxidant property.

Aging↗