Role of adenosine in functional hyperemia in skeletal muscle as indicated by pharmacological tools.

The hypothesis that adenosine mediates blood flow increments in contracting skeletal muscle was evaluated by intravital microscopy of the microcirculation in the tenuissimus muscle of anesthetized rabbits. Motor nerve stimulation elicited muscle contractions and frequency-dependent arteriolar dilatation, particularly in terminal arterioles. The pulse duration (0.

Endothelin modulation of neuroeffector transmission in smooth muscle.

In a series of muscle preparations, the peptides endothelin-1 (ET-1) and endothelin-3 (ET-3) were investigated for effects on basal muscle tone, responses to transmural nerve stimulation, and release of [3H]norepinephrine or [3H]acetylcholine. ET-1 and ET-3 contracted rat vas deferens and guinea pig ileum, ET-1 being the most potent. In the guinea pig taenia coli, ET-1 induced a relaxation whereas ET-3 was almost without relaxing effect.

Endothelin modulation of neuroeffector transmission in rat and guinea pig vas deferens.

The effects of endothelin-1 (human, porcine) on contractions induced by transmural nerve stimulation, exogenous ATP or noradrenaline, and on the release of [3H]noradrenaline were studied in guinea pig and rat vas deferens. Endothelin enhanced nerve-induced contractile responses, increased basal muscle tone and increased the contractile response to exogenous ATP in both guinea pig and rat vas deferens. Endothelin did not affect the contractile responses to exogenous noradrenaline.

Development of rancidity in salmonoid steaks during retail display. A comparison of practical storage life of wild salmon and farmed rainbow trout.

The quality of wild salmon and farmed rainbow trout from aquaculture, both packed in transparent vacuum-skin packaging, was followed during storage for 6 months in an illuminated freezer cabinet (product temperature -17 degrees C, half of the packs protected against light, and half of the packs fully exposed to light), combining (a) colour determination of the carotenoid-pigment flesh by tristimulus colorimetry, (b) determination of thiobarbituric-acid-reactive substances (TBA value), (c) carotenoid analysis and, at the end of the storage experiment, (d) sensory evaluation. Rancidity developed faster in steaks of wild salmon (TBA increased during 6 months of storage from 2.8 mumols malonaldehyde/kg flesh to 12.

Adenosine modulation of resting vascular tone in rabbit skeletal muscle.

The effects of adenosine and adenosine antagonists on arteriolar vessel diameters were studied in the rabbit tenuissimus muscle in situ by means of intravital microscopy. Topically applied adenosine dose-dependently dilated transverse and terminal arterioles, an effect which was competitively antagonized by alkylxanthines. Topically applied alkylxanthines per se evoked dose-dependent vasoconstriction with the same potency order as for their adenosine antagonism.