Antiparkinsonian-like effects of Plumbago scandens on tremorine-induced tremors methodology.

Tremorine-induced tremors model is used to evaluate antiparkinsonian drugs because rest tremor is a sign that distinguishes Parkinson's disease (PD) from other diseases. The effects of crude ethanolic extract (CEE) and total acetate fraction (TAF) of Plumbago scandens were investigated at several doses. These extracts at doses of 125 and 250 mg/kg i.p. failed to reduce tremors in tremorine-treated mice. TAF showed significant effects only at a dose of 500 mg/kg. Both CEE and TAF at doses of 1000 and 2000 mg/kg i.p. suppressed the tremors in a dose-dependent fashion for 60 min. Biperiden, an anticholinergic drug, was used as standard at a dose of 3 mg/kg i.p. This study suggests that P. scandens is a plant with possible therapeutic value for PD.

Pimprinine, an extracellular alkaloid produced by Streptomyces CDRIL-312: fermentation, isolation and pharmacological activity.

Pimprinine, an extracellular alkaloid has been isolated from the culture filtrate of Streptomyces CDRIL-312. Pimprinine was subsequently purified using silica gel column chromatography and also by preparatory thin layer chromatography. Some physicochemical properties, antimicrobial activities (in-vitro) and pharmacological activities of pimprinine were studied. Pimprinine showed promising anticonvulsant activity in both minimum and maximum electric seizure threshold test in mice. Its anticonvulsant activity is very much comparable to that of phenyl hydantion sodium. Pimprinine also inhibited effectively tremorine-induced tremors and analgesia in mice.

Ultrasonic analysis of tremorine and cold tremor activity in unanesthetized rats.

In order to quantify the tremorine and cold tremor activity in unanesthetized rats, a new ultrasonic motion transducer method was used. Both kinds of activity are reported as vibratory body motion that occurred between 18-32 Hz as determined by spectral analysis. The recorded signal was analyzed and its power spectrum was obtained through a fast Fourier transform operation. It was found that a negative linear relation occurs between shiver amplitude and ambient temperature (r = 0.999). A negative linear relation also occurs between metabolic rate and ambient temperature (r = 0.997). In addition, a positive linear relation between metabolic rate and cold shiver exists (r = 0.999). Both tremorine (30 mg/kg, i.p.) and cold tremor (Ta = 2-22 degrees C) activity monitored by the ultrasonic method were completely abolished by premedication with 1 mg/kg atropine. Thus, it appears that the advantages of this tremor detection method are that is non-invasive and non-contact. Therefore, the ultrasonic method provides a good choice for quantifying tremorine and cold tremor activity in unanesthetized animals during studies of thermoregulatory physiology or motor disorders.

The automated analysis of coordinated hindlimb movement in rats during acute and prolonged exposure to toxic agents.

The effects of CNS-active drugs and neurotoxic agents on motor coordination in the rat were studied using a newly developed, automated technique. In this test, a tv/microprocessor-based system was utilized to detect and describe the movement and placement characteristics of one of the rat's hindpaws as the rat placed its paw from one rung to another while walking in a rotating wheel. In studies employing a wheel speed of 8.2 cm/sec and a single 90-sec trial, significant deficits in coordinated hindlimb movement could be detected following the acute ip administration of a variety of compounds, including acrylamide (0, 50, and 100 mg/kg), diazepam (0, 0.5, 1.0, and 2.0 mg/kg), ethyl alcohol (0, 600, 900, and 1200 mg/kg), and tremorine (0, 2.5, 5.0, and 10.0 mg/kg). Further, results from a subacute study involving the oral administration of 2,5-hexanedione (2,5-HD; 0, 250, and 600 mg/kg) indicated that rats treated with 600 mg/kg, 2,5-HD were significantly impaired after 1 week of treatment and those treated with 250 mg/kg 2,5-HD, after 2 weeks of treatment. Although both groups improved during the recovery period, the performance of the 600 mg/kg group 5 weeks post-treatment was still inferior to controls. Taken together, these studies indicate that the coordinated hindlimb placement test provides a reliable, sensitive, and rapid technique for quantifying deficits in motor coordination in the rat during acute and prolonged exposure to neurotoxic substances.