The use of prostaglandins as local antithrombotic agents in microvascular surgery

The effectiveness of Prostaglandin E2 and Prostacyclin as a local antithrombotic agent in microvascular anastomoses was tested experimentally in a controlled double-blind trial in rats. Prostaglandin E2 was found to be ineffective whereas Prostacyclin was found to be very effective.

A comparison of the pharmacodynamic profiles of nomifensine and amitriptyline in normal subjects

1 Six healthy male volunteers participated in a double-blind placebo crossover comparison of the pharmacodynamic profiles of single oral doses of 75 mg nomifensine and 50 mg amitriptyline. 2 Nomifensine treatment did not influence salivary flow and did not significantly affect psychomotor performance (critical flicker fusion, pursuit rotor and reaction time): in addition nomifensine had no significant effect on subjective measurements of sedation and concentration. 3 By contrast, amitriptyline treatment significantly reduced salivary flow and was associated with significant sedation and reduced concentration: significant changes in psychomotor performance were also noted. 4 Plasma concentrations of amitriptyline and nomifensine were measured at 2 h. The respective median concentration values were 55.0 ng/ml and 52.0 ng/ml. 5 Ex vivo platelet amine uptake of dopamine (DA) and 5-hydroxytryptamine (5HT) was measured 2 h after each treatment. Both nomifensine and amitriptyline treatment significantly inhibited DA uptake to a similar extent. Amitriptyline treatment additionally inhibited 5-HT uptake.

The effect of some centrally active drugs on corticosterone secretion and metabolism in rats

1. Male rats were treated with morphine sulphate (10 mg/kg), methadone (10 mg/kg) and chlorpromazine (8.0 mg/kg) respectively, for 2 weeks. 2. At the end of this period, the adrenal glands of treated rats had increased in weight. 3. The concentration of corticosterone in the peripheral plasma was significantly lowered in the chlorpromazine-treated rats, increased in the methadone-treated rats and was unchanged in the morphine-treated rats. 4. The metabolic clearance rate of [1,2-3H]corticosterone decreased in the chlorpromazine-treated rats, while only a slight reduction was observed with methadone treatment. 5. These results showed that chronic treatment with either morphine or methadone did not suppress the adrenal function. The possible site of action of chlorpromazine in suppressing corticosterone secretion is discussed.

The effect of berberine on bilirubin excretion in the rat

Berberine-containing herbs have been used in folk medicine to relieve neonatal jaundice. In the present investigation, the acute and chronic effects of berberine on bilirubin excretion were studied in rats. Acute doses of berberine were found to increase the secretion of bilirubin in experimental hyperbilrubinemia without affecting the UDP-glucuronyltransferase activity and BSP clearance. Continuous treatment abolished this effect. This apparent tolerance could be attributed to the inhibitory action of chronic berberine treatment on UDP-glucuronyltransferase activity, but the mechanism of this inhibition was not elucidated. Liver microsomal protein concentration, ethylmorphine N-demethylation, and BSP clearance were unchanged.

The effects of hypophysectomy on the metabolism of adrenal steroids in the pigeon (Columba livia)

The distribution and disappearance of radioactivity after the intravenous administration of [1,2-3H]corticosterone and [1,2-3H]aldosterone to the pigeon were studied according to one- and two-compartment model systems. The volume of distribution (AVD) of the total and methylene chlorideextractable radioactivity in the plasma of hypophysectomized pigeons injected with labelled corticosterone was significantly increased. Also the biological half-life (T½) of each radioactive fraction in plasma was significantly prolonged. No significant change in the metabolic clearance rate (MCR) of labelled corticosterone was observed in the hypophysectomized pigeon.

The AVD of the total and methylene chloride-extractable tritium in the plasma of the hypophysectomized pigeon injected with labelled aldosterone was unchanged but the T½ of both plasma fractions was significantly prolonged. The estimated MCR of labelled aldosterone was significantly diminished.

The concentration of total fluorogenic corticosteroid in plasma from the chronically hypophysectomized pigeon was reduced to one-third of that in the sham-operated bird, and corticotrophin-replacement therapy restored the concentration to normal. After hypophysectomy, the plasma corticosterone concentration was reduced to 20% of the concentration in the sham-operated birds, and replacement therapy with corticotrophin again restored the plasma levels to normal. Estimation of the endogenous corticosterone secretory rates indicated that chronic hypophysectomy was accompanied by a decline commensurate with the reduction in the plasma corticosterone concentration.