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

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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	Unknown	Antagonist Inhibitor Ligand	Details