A pressor effect of noncardioselective beta blockers in mildly hypertensive patients during surgery under anesthesia.

Sixty-two patients with mild hypertension were randomly assigned to receive no treatment, or 160 mg propranolol, or 200 mg metoprolol daily starting one week before elective surgery under anesthesia. The last dose was given two hours before anesthesia. Anesthesia consisted of induction with midazolam (2.

Characterization of dopamine D2 receptors in the pituitary of the African catfish, Clarias gariepinus.

Dopamine receptors in the pituitary of the African catfish, Clarias gariepinus, were characterized using [3H]spiperone as radioligand. Specific binding of [3H]spiperone to pituitary membranes reached equilibrium within 60 min of incubation. The binding of the radioligand was tissue specific since the amount of binding was linear with pituitary membrane content in the incubations.

Role of calcium ions in action of gonadotropin-releasing hormone on gonadotropin secretion in the African catfish, Clarias gariepinus.

The aim of the present study was to establish the role of calcium ions in the mechanism of action of gonadotropin-releasing hormone (GnRH) in stimulating gonadotropin (GTH) release in the African catfish, Clarias gariepinus. For that purpose, GTH release from pituitary fragments was monitored in a perifusion system. GTH release, induced by the GnRH analog Buserelin, was strongly diminished in the absence of Ca2+, as well as in the presence of the Ca2+ channel antagonist nifedipine.

Catecholestrogens inhibit dopamine methylation in the gonadotrops of the African catfish,Clarias gariepinus.

Isolated gonadotrops of the African catfish,Clarias gariepinus, were incubated with dopamine (DA) and/or catecholestrone and the activity of the enzyme catechol-O-methyltransferase (COMT) was determined by measuring the methylated products. From the apparent Km values for DA and catecholestrone of 0.4-1.

Immunocytochemical evidence for peptidergic (GnRH) and dopaminergic innervation of the gonadotropic cells in the pituitary of the African catfish, Clarias gariepinus.

The proximal pars distalis (PPD) of the pituitary of the African catfish, Clarias gariepinus, was studied with immunocytochemical methods at the ultrastructural level. Anti-serum raised against synthetic mammalian luteinizing hormone-releasing hormone (LHRH) was applied on Lowicryl-embedded pituitaries and the antigenic sites were visualized with protein A-gold. In nerve fibers contacting the gonadotropic cells, granulated vesicles with a diameter of 90-120 nm were labeled after this procedure, whereas the glandular cells were not labeled.

Specificity and memory in increased defence reactions against bacteria in the pond snail Lymnaea stagnalis.

In Lymnaea stagnalis injections with dead Escherichia coli or Staphylococcus saprophyticus bacteria resulted in an enhanced clearance of both live S. saprophyticus and E. coli injected 4 days later.