These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Novel 5-HT2-like receptor mediates neurogenic relaxation of the guinea-pig proximal colon.
    Author: Briejer MR, Akkermans LM, Lefebvre RA, Schuurkes JA.
    Journal: Eur J Pharmacol; 1995 Jun 12; 279(2-3):123-33. PubMed ID: 7556392.
    Abstract:
    The aim of the current investigation was to characterize the 5-HT receptors that mediate neurogenic relaxation of the guinea-pig proximal colon. After blockade of 5-HT2A, 5-HT3 and 5-HT4 receptor-mediated contractions, 5-hydroxytryptamine (5-HT) induced relaxations yielding a biphasic concentration-response curve. Other tryptamines were also agonists with the following rank order of potency: 5-HT > 5-carboxamidotryptamine = 5-methoxytryptamine > or = alpha-methyl-5-HT (partial agonist) > tryptamine (partial agonist). 5-Hydroxytryptophan, 2-methyl-5-HT and N-methyltryptamine were virtually inactive as agonists. The curve to 5-HT was not affected by pargyline, citalopram, phentolamine, or by the 5-HT4 receptor antagonists 2-methoxy-4-amino-5-chloro-benzoic acid 2-(diethylamino)ethyl ester (SDZ 205-557) and (1-butyl-4-piperidinylmethyl)-8-amino-7-chloro-1,4-benzodioxan+ ++-5-carboxylate (SB 204070). 8-Hydroxy-2-(di-n-propylamino)-tetralin (8-OH-DPAT), 5-methoxy-3[1,2,3,6-tetrahydroxypyridin-4-yl]-1H-indole (RU 24969), 2-(2,6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane (WB 4101), 1-(3-chlorophenyl)piperazine (mCPP), 1-(m-trifluoromethylphenyl)-piperazine (TFMPP), flesinoxan, sumatriptan and 6-chloro-2-(piperazinyl)-pyrazine (MK212) were inactive as 5-HT receptor agonists. The first phase of the curve to 5-HT was inhibited by: metergoline (pA2 = 8.8 +/- 0.3, against 5-methoxytryptamine 9.3 +/- 0.3), methysergide (non-surmountable), methiothepin (non-surmountable), spiroxatrine (non-surmountable), MK212 (non-surmountable), mesulergine (7.8 +/- 0.3), mCPP (7.1 +/- 0.1), mianserin (7.0 +/- 0.4), ritanserin (8.9 +/- 0.2), rauwolscine (7.0 +/- 0.2), yohimbine (6.2 +/- 0.2), 1-(1-naphthyl)-piperazine (7.7 +/- 0.2) and RU 24969 (6.4 +/- 0.1), but not by 1-(2-methoxyphenyl)4-[4-(2-phthalimidobtyl]-piperazine (NAN-190), spiperone, sumatriptan, 8-OH-DPAT and flesinoxan. It is suggested that the 5-HT receptor under study could be considered an unknown 5-HT2-like receptor.
    [Abstract] [Full Text] [Related] [New Search]