Martin Pfaffendorf

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T-type calcium channels may be involved in the maintenance of myogenic tone. We tested their role in isolated rat cremaster arterioles obtained after CO(2) anesthesia and decapitation. Total RNA was analyzed by RT-PCR and Southern blotting for calcium channel expression. We observed expression of voltage-operated calcium (Ca(V)) channels Ca(V)3.1 (T-type),(More)
OBJECTIVE Several studies have shown that arginine vasopressin (AVP) potentiates the sympathetic nervous transmission in isolated vessels. The present study investigates such a potentiation in the pithed rat model. METHODS Male Wistar rats weighing 270-310 g were used. Spinal-cord stimulation was applied, with frequencies of 0.25-4 Hz, in the presence or(More)
In the present study, we investigated if the relaxant effects of phosphodiesterase (PDE) III inhibitors on human vessels could be inhibited by a nitric oxide synthase blocker, L-NAME, or by a blocker of ATP-sensitive potassium channels (KATP), glibenclamide. The experiments were performed using an isometric myograph in isolated human s.c. small arteries(More)
1. The present study was designed to analyse the possible involvement of V1- and V2-receptors in vasopressin (AVP)-induced facilitation of the sympathetic nervous system. Furthermore, we aimed to determine whether the site of facilitation by AVP is located pre- or postsynaptically. 2. Electrical field stimulation (EFS) was applied on the rat mesteric artery(More)
This study tested whether mibefradil exerts a stronger inhibitory effect than verapamil on sympathetic neurotransmitter release provoked by electrical field stimulation. Tail arteries (diameter 620+/-9 microm) were obtained from male Wistar rats. Ring segments of 2 mm length were mounted in an isometric wire myograph. After an appropriate period of(More)
1. The effects of several agonists on the phasic and tonic contractile responses to muscarinic receptor stimulation have been investigated in the rat portal vein in vitro. 2. Neither chemical denervation with 6-hydroxydopamine nor the presence of the alpha 1-adrenoceptor antagonist, prazosin, influenced the spontaneous or the stimulated myogenic activity of(More)
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