5-HT4 receptors in isolated human corpus cavernosum?
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Hayes ES, Adaikan PG, Ratnam SS, Ng SC
5-HT4 receptors in isolated human corpus cavernosum?
Int J Impot Res. 1999 Aug;11(4):219-25. doi: 10.1038/sj.ijir.3900425.
- PubMed ID
- 10467522 [ View in PubMed]
- Abstract
The novel serotonin subtype-4 (5-HT4) receptor agonist, SC53116 (SC), produced a limited relaxation of noradrenaline (NA) pre-contracted human corpus cavernosum (CC) smooth muscle in vitro. This effect was not significantly attenuated by the 5-HT4 antagonist SDZ250557 (SDZ). In the presence of (+/-) pindolol (1 microM) and methysergide (1 microM), employed to mask 5-HT1 and beta-adrenergic, and 5-HT2 receptors respectively, SC failed to relax NA pre-contracted CC strips to a greater extent than saline. Functional cAMP dependent relaxation pathways were demonstrated by a significant reduction in NA induced tone by prostaglandin E1 (PGE1) and isopropylnoradrenaline (IPNA), the action of the latter compound was effectively eliminated in the presence of (+/-) pindolol. Relaxation of NA induced tone caused by the nitric oxide donor nitro-glycerine (NTG) was significant and similar in the absence and presence of the 5-HT and beta-adrenergic antagonists. The results of this present study indicate that human corporal smooth muscle does not contain 5-HT4 receptors and that, although compounds like SC act to relax non-vascular smooth muscle via cAMP dependent mechanisms, 5-HT4 receptor agonists may be expected to be of limited utility in triggering cAMP dependent relaxation responses in human CC.
DrugBank Data that Cites this Article
- Drug Targets
Drug Target Kind Organism Pharmacological Action Actions Pindolol 5-hydroxytryptamine receptor 1A Protein Humans UnknownAntagonistInhibitorLigandDetails