Characterization of prejunctional $5-HT_{1}$ receptors that mediate the inhibition of pressor effects elicited by sympathetic stimulation in the pithed rat

Content Provider	Scilit
Author	Morán, A. Fernández, M. M. Velasco, C. Martín, M. L. Román, L. San
Copyright Year	1998
Description	Journal: British Journal of Pharmacology 1. A study was made of the effects of 5-carboxamidotryptamine (5-CT) on pressor responses induced in vivo by electrical stimulation of the sympathetic outflow from the spinal cord of pithed rats. All animals had been pretreated with atropine. Sympathetic stimulation (0.1, 0.5, 1 and 5 Hz) resulted in frequency-dependent increases in blood pressure. Intravenous infusion of 5-CT at doses of 0.01, 0.1 and 1 mg kg(-1) min(-1) reduced the pressor effects obtained by electrical stimulation. The inhibitory effect of 5-CT was significantly more pronounced at lower frequencies of stimulation. In the present study we characterized the pharmacological profile of the receptors mediating the above inhibitory effect of 5-CT. 2. The inhibition induced by 0.01 microg kg(-1) min(-1) of 5-CT on sympathetically-induced pressor responses was partially blocked after i.v. treatment with methiothepin (10 microg kg(-1)), WAY-100,635 (100 microg kg(-1)) or GR127935T (250 microg kg(-1)), but was not affected by cyanopindolol (100 microg kg(-1)). 3. The selective 5-HT1A receptor agonist 8-OH-DPAT and the selective 5-HT(1B/1D) receptor agonists sumatriptan and L-694,247 inhibited the pressor response, whereas the 5-HT1B receptor agonists CGS-12066B and CP-93,129 and the 5-HT2C receptor agonist m-CPP did not modify the pressor sympathetic responses. 4. The selective 5-HT1A receptor antagonist WAY-100,635 (100 microg kg(-1)) blocked the inhibition induced by 8-OH-DPAT and the selective 5-HT(1B/1D) receptor antagonist GR127935T (250 microg kg(-1)) abolished the inhibition induced either by L-694,247 or sumatriptan. 5. None of the 5-HT receptor agonists used in our experiments modified the pressor responses induced by exogenous noradrenaline (NA). 6. These results suggest that the presynaptic inhibitory action of 5-CT on the electrically-induced pressor response is mediated by both r-5-HT1D and 5-HT1A receptors.
Related Links	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1565267/pdf
Ending Page	1213
Page Count	9
Starting Page	1205
e-ISSN	14765381
DOI	10.1038/sj.bjp.0701714
Journal	British Journal of Pharmacology
Issue Number	6
Volume Number	123
Language	English
Publisher	Wiley-Blackwell
Publisher Date	1998-03-01
Access Restriction	Open
Subject Keyword	Journal: British Journal of Pharmacology 5-hydroxytryptamine R-5-ht1d Receptors 5-ht1-like Receptors Prejunctional Inhibition
Content Type	Text
Resource Type	Article