Isolated central ear arteries of rabbits were perfused with Krebs solution at a constant flow rate of 2-7 ml/min. Pressure changes to periarterial nerve stimulation (1, 3, 10 and 30 Hz; 5-32 pulses) and to noradrenaline were measured in the presence and absence of prostaglandin E1 (PGE1). This substance in concentrations of 7 × 10-9- 4.5 × 10-7 produced a dose-dependent inhibition of constrictor responses to nerve stimulation. The degree of inhibitory action of PGE1 became progressively less as the frequency or length of stimulation was increased. Prostaglandin E1 (1.1 × 10-7 M) failed to affect the constrictor responses to noradrenaline and it markedly reduced the stimulation-evoked release of radioactivity from arteries incubated with noradrenaline. The results indicate that PGE1 inhibits the vasoconstrictor responses of rabbit ear artery to nerve stimulation by reducing the release of the adrenergic transmitter.
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience