Beeinflussung des pressorischen Eserin-Effekts durch Propranolol

Tyrosine hydroxylase activity in rat brain regions after chronic treatment with +/--propranolol

Rats were injected twice daily with +/--propranolol (6 mg kg-1 day-1) for 14 days and killed 16 h after the final injection. Tyrosine hydroxylase activity was measured in both soluble and particle-bound forms in various brain regions. The activity of the soluble enzyme was not significantly altered by propranolol treatment in any of the brain regions studied. The tyrosine hydroxylase activity in the particulate fraction was significantly increased in corpus striatum and unchanged in other brain regions. The propranolol concentrations in the various brain regions in this chronic study were far lower than necessary to produce a significant change in tyrosine hydroxylase activity in acute experiments. It was concluded that chronic propranolol treatment produces a persistent increase in bound tyrosine hydroxylase activity in rat corpus striatum.

Propranolol uptake into the central nervous system and the effect on rat behaviour and amine metabolism

Propranolol readily penetrated all areas of the central nervous system after acute intraperitoneal administration and was cleared within 8–16 hr. Propranolol levels in the heart followed a similar pattern. After chronic oral administration brain levels of propranolol were equal to those 3 hr after intraperitoneal injection. Propranolol caused no significant difference in the brain levels of noradrenaline, normetanephrine, dopamine, 3-methoxytyramine, homovanillic acid, 5-hydroxy-tryptamine or total indoles, nor did it cause measurable changes in rat behaviour. An increase by propranolol in sleeping time after chloral hydrate in rats and mice was observed; this effect could not be correlated with changes in brain amine concentrations.