Browsing by Author "D. Hota"

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Neuropharmacological studies on Fusarium toxins - I: Total toxin extract from Fusarium moniliforme
(1996) Snigdha Ganguli; D. Hota; R.K. Goel; S.B. Acharya; S.K. Bhattacharya
The neuropharmacological profile of the total fungal extract of F. moniliforme (FM) has been investigated. FM produced dose related decrease in spontaneous motor activity (SMA) and exploratory activity, potentiated pentobarbitone hypnosis and the anticonvulsant actions of phenobarbitone and phenytoin against MES seizures, potentiated PTZ and tryptamine seizures, antagonised reserpine induced syndrome, attenuated tetrabenazine and morphine induced catalepsy and potentiated haloperidol catalepsy. FM showed per se antinociceptive activity and potentiated morphine analgesia. It increased rectal temperature, antagonised reserpine and apomorphine hypothermia and potentiated the hyperthermic response of haloperidol and 5-hydroxytryptophan (5-HTP) and hypothermic response of betaphenylethylamine (PEA) and L-dopa. FM had no per se effect on amphetamine lethality, but enhanced the lethality induced by morphine in aggregated animals. Stereotypy by amphetamine was potentiated while that of apomorphine was not affected. The behavioural response of 5-HTP and L-dopa was potentiated. FM had no effect on swim induced behavioural despair. The effect on aggressive behaviour was complex, and while the cumulative aggressive score was reduced, the onset of fighting behaviour and contact period was increased. It also inhibited clonidine induced auto mutilation. Since earlier investigation had shown that FM, like nialamide, induced non-selective inhibition of monoamine oxidase (MAO), the results were compared with those induced by nialamide. A comparative profile of action reveals that the neuropharmacological action of FM are qualitatively similar to those induced by nialamide, and likely to be due to inhibition of MAO. The investigation has practical implications because F. moniliforme is a common contaminant of cereals and fruits.
Neuropharmacological studies on Fusarium toxins - III: Neurochemical investigations on total toxin extracts from F. moniliforme and F. oxysporum
(1996) Snigdha Ganguli; D. Hota; R.K. Goel; S.B. Acharya; S.K. Bhattacharya
Neurochemical effects of different fusarial toxins elaborated from F. moniliforme (FM) and F. oxysporum (FO) were investigated. FM showed significant nonspecific and irreversible monoamine oxidase (MAO) inhibition which was qualitatively comparable to that induced by nialamide, a nonselective MAO inhibitor. FO did not exhibit any significant MAO inhibitory effect. FM produced a dose related increase in monoamine concentrations (dopamine, noradrenaline and 5-hydroxytryptamine) in different rat brain areas namely, diencephalon-midbrain, caudate nucleus and pons-medulla. FO, on the contrary, produced marked increase in dopamine concentration in the caudate nucleus with concomitant reduction in noradrenaline levels in diencephalon-midbrain and pons-medulla with little effect on 5-HT concentration. The neurochemical effects of FM and FO are consonant with the earlier reports on the neuropharmacological profile of these toxins. Thus, FM was reported to have nialamide like activity, whereas FO actions were dopaminergic in nature.
Neuropharmacological studies on Fusarium toxins-II: Total toxin extract from F. oxysporum
(1996) Snigdha Ganguli; D. Hota; R.K. Goel; S.B. Acharya; S.K. Bhattacharya
The neuropharmacological activity profile of total fungal extract of F. oxysporum (FO) was investigated. FO enhanced spontaneous locomotor activity, exploratory behaviour and reduced pentobarbitone hypnosis. It has per se anticonvulsant action against maximal electroshock seixure (MES) and potentiated phenobarbitone and phenytoin in MES and also potentiated pentylenetetrazol (PTZ) convulsion. It antagonised morphine, tetrabenazine and haloperidol catalepsy. FO did not show per se analgesia or potentiation of morphine antinociception in mice, while both effects were present in rats. The effect of FO on body temperature was complex. It produced per se reduction in rectal temperature and potentiated the hypothermic responses of reserpine, apomorphine, PEA and l-dopa, and also the hyperthermic response of 5-HTP. The hyperthermic response of haloperidol was reversed by FO. It potentiated amphetamine and morphine lethality, amphetamine, PEA and apomorphine stereotypy, 5-HTP headtwitch response and post-swim grooming response. On swim-stress immobility, while the time of onset of immobility was reduced, FO dit not modify the duration of immobility. On foot-shock induced aggression in paired rats, FO produced a decrease in the latency to onset of fighting behaviour and increased the total contact period and the cumulative aggressive score. FO potentiated clonidine automutilation. It has, thus, facilitated aggressive behaviour. The effects are likely to be due to the presence of fusaric acid in FO, which inhibits dopamine β-hydroxylase and is known to have dopaminergic effects. This investigation has practical implications, since F.oxysporum is a common food contaminant.
Role of prostaglandin synthesis inhibitors on chemically induced seizures
(1995) J. Bhaduri; D. Hota; S.B. Acharya
The study was conducted to find out the possible role of prostaglandin synthesis inhibitors on different parameters of chemically induced seizures in albino mice. The results suggest that prostaglandins have a proconvulsant activity. Augmentation of central dopamine and serotonin levels is partly responsible for the inhibitory effect of prostaglandin synthesis inhibitors on chemically induced seizures.
Studies on peripheral actions of isatin
(1994) D. Hota; S.B. Acharya
The possible peripheral actions of isatin were studied in vivo and in vitro preparations in different experimental models, using conventional techniques. The results showed spasmogenic responses of isatin on guinea pig, rat and rabbit ileum and fundus of rat stomach. Histamine induced broncho-constriction could be antagonised by isatin. Isatin had cardioinhibitory effect on isolated frog heart and had hypotensive and respiratory depressant activities in dog. Isatin had antidiuretic effect. It was devoid of any effect on inflammation and gastric activities. The present results suggest a possible involvement of heterogenic 5-HT3 receptors in gastrointestinal smooth muscle.