Developmental and neurobehavioural toxicity study of arsenic on rats following gestational exposure.

To characterize developmental and behavioral alterations induced by arsenic exposure, Albino rats were exposed to arsenic (0, 1.5, 3.0 and 4.5 mg/kg/day/po) from gestation day 8 to till parturition and the offspring were observed over the first 3 postnatal weeks, until they were weaned on post-natal day (PND) 21. Once the pups were delivered (PND0), the treatment was discontinued. All pups were assessed for physical development, reflex development, strength and motor coordination from standard neurobehavioural developmental test batteries beginning on PND1. Gestational administration of arsenic at tested dose levels, showed no significant changes in the day of appearance of eye opening, startle reflex, negative geotaxis and spontaneous alteration performance in comparison to the control group. The number of live fetuses, mean fetal body weight and percentages of resorptions or malformations per litter were not affected by arsenic exposure. No treatment-related malformations or developmental variations were noted at any exposure level, suggesting that arsenic exposure at this dose level did not adversely affect behavioural endpoints of developmental toxicity.

Effect of lead on anorexia and body weight in albino rats.

Rats exposed to lead (lead acetate) in doses of 0.2 and 0.5 mg/ml in drinking water for a period of 90 days showed mild to moderate changes in food consumption compared to control group. Drug interactions in lead exposed rats with metoclopramide, atropine sulphate, propranolol, cyproheptadine and mepyramine maleate when administered intraperitoneally caused -30 to +30 percentage variation in food intake indicating the influence of adrenergic, serotonergic and cholinergic neurotransmitters with no change in mean body weight of lead treated rats.

In vitro study of rat uterus after chronic formaldehyde exposure.

To measure cholinergic, adrenergic and tryptaminergic receptor activity of formaldehyde (HCHO) in rat uterus, albino rats were treated with 5 and 10 mg/kg, ip HCHO for 30 days. Acetylcholine (ACh) in doses 1.33, 2 and 3 micrograms/ml produced mild to moderate contraction of isolated rat uterus in control group. HCHO had no effect on isolated rat uterus per se, however it reduced ACh and carbachol induced contraction and presence of adrenaline influences in respect of ACh and carbachol activity. Adrenaline per se had no effect in control preparations, but reduced carbachol induced contraction. Propranolol had no effect on rat uterus; but its presence in the bathing medium increased activity of adrenaline. 5-Hydroxytryptamine (5-HT) had no effect of its own on isolated rat uterus but its presence in the bathing medium enhanced contractions of carbachol and oxytocin.

Behavioural change in rats due to chronic oral and systemic formaldehyde.

Impact of chronic formaldehyde exposure in respect of route on behaviour was studied. Preconditioned (environmental) male albino rats (340-400 g) in 3 groups (n = 5) under 60 days oral and systemic exposure to 10 mg/kg/day HCHO were examined for their behavioural performance (i.e. short term memory) in Cook's apparatus. Twenty percent rats settled in grade III (unconditioned avoidance response) in the i.p. (i.e. systemic group) whereas in oral fed (HCHO route in drinking water) rats, 60% settled in grade II (conditioned avoidance response) at the end of sixty days.

Pharmacology of Acorus calamus L.

Water soluble dried powder of alcoholic extract of roots and rhizomes of A. calamus L. was used. The in vivo experiments involved strychnine convulsant activity in frogs, spontaneous motor activity and amphetamine hyperactivity in mice, pentobarbitone sleeping-time in rats and local anaesthetic activity in guinea pigs and rabbits. Frog skeletal muscle and heart preparations and rat phrenic nerve diaphragm constituted the in vitro experiments. Plant extracts at 10, 20 mg/kg ip did not afford protection to strychnine (1,5,2.5 mg/kg) induced convulsions and same effect was found on acetylcholine induced contractions of rectus muscle except that it inhibited caffeine citrate contractions in frog. At 1, 10 and 100 micrograms/ml doses, it caused negative iono- and chronotropic effects in frogs. Dosages of 10, 25, 50 mg/kg ip of herbal extract antagonize spontaneous motor activity and also amphetamine induced hyperactivity in mice. It was less potent than chloropromazine, though exerts sedative and tranquilizing action. Local anaesthetic activity was found to be absent at 0.5 and 1% dose levels.