5-HT1B Receptor Subtype and Aging in Rat Resistance VesselsFroldi G. · Montopoli M. · Zanetti M. · Dorigo P. · Caparrotta L.
Departments of aPharmacology and Anaesthesiology and bHistology, Microbiology, and Medical Biotechnologies, University of Padova, Padova, Italy
The effects of 5-hydroxytryptamine (5-HT), 5-carboxamidotryptamine, and sumatriptan on rat caudal arteries were examined, with the goal of finding experimental conditions useful in enhancing the ‘silent’ 5-HT1B receptor subtype. It was shown that both reserpine treatment and K+ depolarizationincreased the vasoconstriction by 5-HT receptor agonists. The role of the 5-HT2A receptor in vasoconstriction was examined using ritanserin (50 nmol/l), a selective 5-HT2A antagonist, whereas that of the ‘silent’ 5-HT1B receptor was examined using SB-224289 (0.2 µmol/l), a selective 5-HT1B receptor antagonist. The influence of age on the ‘silent’ 5-HT1B receptor subtype was also investigated; for this, the effect of sumatriptan, a selective 5-HT1B/1D agonist, was tested on arterial tissues of both young and old rats which had been either K+ depolarized or reserpine treated or both. It was found that aging strongly shifted the concentration-vasoconstriction curve generated by sumatriptan to the left, also increasing the maximum contractile response, mainly in reserpine-treated tissues. RT-PCR was used to study the expression of 5-HT1B and 5-HT2A receptors in both young and old tissues. The results support the idea that reserpine-treated and K+-depolarized caudal arteries from old rats can be a pharmacological model which is useful in highlighting the ‘silent’ 5-HT1B receptor subtype.
|Direct payment||This item at the regular price: USD 38.00|
|Payment from account||With a Karger Pay-per-View account (down payment USD 150)
you profit from a special rate for this and other single items.
This item at the discounted price: USD 26.50