2-Methyl-5-hydroxytryptamine hydrochloride

Human-derived gut microbiota modulates colonic secretion in mice by regulating 5-HT3 receptor expression via acetate production.[Pubmed:28408644]

Am J Physiol Gastrointest Liver Physiol. 2017 Jul 1;313(1):G80-G87.

Serotonin [5-hydroxytryptamine (5-HT)], an important neurotransmitter and a paracrine messenger in the gastrointestinal tract, regulates intestinal secretion by its action primarily on 5-HT3 and 5-HT4 receptors. Recent studies highlight the role of gut microbiota in 5-HT biosynthesis. In this study, we determine whether human-derived gut microbiota affects host secretory response to 5-HT and 5-HT receptor expression. We used proximal colonic mucosa-submucosa preparation from age-matched Swiss Webster germ-free (GF) and humanized (HM; ex-GF colonized with human gut microbiota) mice. 5-HT evoked a significantly greater increase in short-circuit current (DeltaIsc) in GF compared with HM mice. Additionally, 5-HT3 receptor mRNA and protein expression was significantly higher in GF compared with HM mice. Ondansetron, a 5-HT3 receptor antagonist, inhibited 5-HT-evoked DeltaIsc in GF mice but not in HM mice. Furthermore, a 5-HT3 receptor-selective agonist, 2-Methyl-5-hydroxytryptamine hydrochloride, evoked a significantly higher DeltaIsc in GF compared with HM mice. Immunohistochemistry in 5-HT3A-green fluorescent protein mice localized 5-HT3 receptor expression to enterochromaffin cells in addition to nerve fibers. The significant difference in 5-HT-evoked DeltaIsc between GF and HM mice persisted in the presence of tetrodotoxin (TTX) but was lost after ondansetron application in the presence of TTX. Application of acetate (10 mM) significantly lowered 5-HT3 receptor mRNA in GF mouse colonoids. We conclude that host secretory response to 5-HT may be modulated by gut microbiota regulation of 5-HT3 receptor expression via acetate production. Epithelial 5-HT3 receptor may function as a mediator of gut microbiota-driven change in intestinal secretion.NEW & NOTEWORTHY We found that gut microbiota alters serotonin (5-HT)-evoked intestinal secretion in a 5-HT3 receptor-dependent mechanism and gut microbiota metabolite acetate alters 5-HT3 receptor expression in colonoids.View this article's corresponding video summary at https://www.youtube.com/watch?v=aOMYJMuLTcw&feature=youtu.be.

Role of supraspinal serotonin receptors for micturition in normal conscious rats.[Pubmed:11948716]

Neurourol Urodyn. 2002;21(3):225-30.

Serotonin (5-HT) receptors are widely distributed in the central nervous system, including several areas involved in the control of micturition reflex pathways. However, the roles of the different subtypes of 5-HT receptors are not well known. We studied in normal, conscious rats, the effects on the cystometrogram of intracerebroventricular (i.c.v.) administration of 5-HT, 8-hydroxy-2-(di-N-propylaminotetralin) (8-OH-DPAT; agonist at 5-HT(1A) receptors), alpha-methyl-5-hydroxytryptamine maleate (agonist at 5-HT(2) receptors), 2-Methyl-5-hydroxytryptamine hydrochloride (agonist at 5-HT(3) receptors), and 1-(4-amino-5-chloro-2methoxyphenyl)-3-(1-n-butyl-4piperidinyl)-1-propanone hydrochloride (RS67506; agonist at 5-HT(4) receptors). Female Sprague-Dawley rats, weighing approximately 230 g, were used. A polyethylene catheter was inserted into the bladder through the dome for cystometric investigations. For administration of drugs, a catheter was implanted into the right cerebral ventricle. Three days after implantation of the bladder catheter, continuous cystometry was performed. Administration of 5-HT (6 nmol/kg i.c.v.), 8-OH-DPAT (6 nmol/kg), alpha-methyl-5-hydroxytryptamine maleate (6 nmol/kg), or RS67506 hydrochloride (6 nmol/kg) significantly (P < 0.05) increased micturition pressure and decreased bladder capacity and micturition volume. The effects increased in a dose-dependent manner (18, 60 nmol/kg). Intracerebroventricular administration of 2-Methyl-5-hydroxytryptamine hydrochloride (60 nmol/kg) caused no change in the cystometric parameters. The results suggest that in normal conscious rats, at the supraspinal level, 5-HT (via 5-HT(1A), 5-HT(2), and 5-HT(4) receptors) can enhance the micturition reflex induced by bladder filling. Whether this means that 5-HT(1A), 5-HT(2), and 5-HT(4) receptors can be targets for drugs meant for treatment of bladder hyperactivity, should be explored.

2-Substituted tryptamines: agents with selectivity for 5-HT(6) serotonin receptors.[Pubmed:10715164]

J Med Chem. 2000 Mar 9;43(5):1011-8.

Several 2-alkyl-5-methoxytryptamine analogues were designed and prepared as potential 5-HT(6) serotonin agonists. It was found that 5-HT(6) receptors accommodate small alkyl substituents at the indole 2-position and that the resulting compounds can bind with affinities comparable to that of serotonin. In particular, 2-ethyl-5-methoxy-N, N-dimethyltryptamine (8) binds with high affinity at human 5-HT(6) receptors (K(i) = 16 nM) relative to 5-HT (K(i) = 75 nM) and was a full agonist, at least as potent (8: K(act) = 3.6 nM) as serotonin (K(act) = 5.0 nM), in activating adenylate cyclase. Compound 8 displays modest affinity for several other populations of 5-HT receptors, notably h5-HT(1A) (K(i) = 170 nM), h5-HT(1D) (K(i) = 290 nM), and h5-HT(7) (K(i) = 300 nM) receptors, but is otherwise quite selective. Compound 8 represents the first and most selective 5-HT(6) agonist reported to date. Replacing the 2-ethyl substituent with a phenyl group results in a compound that retains 5-HT(6) receptor affinity (i.e., 10: K(i) = 20 nM) but lacks agonist character. 2-Substituted tryptamines, then, might allow entry to a novel class of 5-HT(6) agonists and antagonists.

5-Methoxytryptamine and 2-methyl-5-hydroxytryptamine-induced desensitization as a discriminative tool for the 5-HT3 and putative 5-HT4 receptors in guinea pig ileum.[Pubmed:2402303]

Naunyn Schmiedebergs Arch Pharmacol. 1990 Jul;342(1):9-16.

Agonist-induced desensitization has been utilized to discriminate and independently "isolate" the neuronal excitatory receptors to 5-hydroxytryptamine (5-HT) in the guinea pig ileum (5-HT3 and putative 5-HT4 receptors). Electrically stimulated longitudinal muscle myenteric plexus preparations, and non-stimulated segments of whole ileum were used. Exposure to 5-methoxytryptamine (10 mumol/l) inhibited completely responses to 5-HT at the putative 5-HT4 receptor without affecting 5-HT3-mediated responses. Conversely, exposure to 2-methyl-5-HT (10 mumol/l) inhibited completely responses to 5-HT at the 5-HT3 receptor without affecting putative 5-HT4-mediated responses. The inhibition with 5-methoxytryptamine and 2-methyl-5-HT, either alone or in combination, appeared selective as responses to KCl, DMPP, carbachol, histamine, and substance P were unaffected or only very slightly modified. Furthermore, the pA2 values for ICS 205-930 at the putative 5-HT4 (pA2 = 6.2 to 6.5) and 5-HT3 (pA2 = 7.6 to 8.1) receptors (estimated in the presence of 2-methyl-5-HT and 5-methoxytryptamine, respectively) were consistent with those estimated in the absence of desensitization. 5-Methoxytryptamine, but not 2-methyl-5-HT, suppressed completely but reversibly the concentration-effect curve to renzapride, suggesting that responses to this agent are mediated exclusively via agonism at the putative 5-HT4 receptor. It is concluded that 5-methoxytryptamine and 2-methyl-5-HT can be utilized as selective probes to discriminate the putative 5-HT4 receptor from the 5-HT3 receptor in guinea pig ileum. This finding is of importance as no selective antagonist exists for the putative 5-HT4 receptor.(ABSTRACT TRUNCATED AT 250 WORDS)

5-HT1 and 5-HT2 binding profiles of the serotonergic agents alpha-methylserotonin and 2-methylserotonin.[Pubmed:2299641]

J Med Chem. 1990 Feb;33(2):755-8.

alpha-Methyl-5-hydroxytryptamine (alpha-Me-5-HT; 2) and 2-methyl-5-hydroxytryptamine (2-Me-5-HT; 3) are considered to be 5-HT2-selective and 5-HT3-selective agents, respectively. These agents were synthesized and examined at serotonin (5-HT) binding sites because there is relatively little documentation as to their selectivity and because they have not been previously examined at the newly discovered 5-HT1D and 5-HT1E sites. As previously reported, 2-Me-5-HT possesses a low affinity (Ki greater than 500 nM) for 5-HT1A, 5-HT1B, 5-HT1C, and 5-HT2 sites; this agent also displays a low affinity for 5-HT1D (Ki = 1220 nM) and 5-HT1E (Ki greater than 10,000 nM) sites. However, alpha-Me-5-HT displays little selectivity for 5-HT1A, 5-HT1B, 5-HT1C, and 5-HT1D sites (Ki = 42, 85, 150, and 150 nM, respectively) and a very low affinity for 5-HT1E (Ki greater than 10,000 nM) sites. Depending upon the radioligand used to label the sites, alpha-Me-5-HT displays either a low affinity (Ki = 880 nM with [3H]ketanserin) or a high affinity (Ki = 3 nM with [3H]DOB) for 5-HT2 sites. These results suggest that alpha-Me-5-HT is not as selective as previously considered and that caution should be used when employing this agent in pharmacological studies because it may act as mixed 5-HT1/5-HT2 agonist.

5-Hydroxytryptamine3 receptors mediate tachycardia in conscious instrumented dogs.[Pubmed:1968974]

J Pharmacol Exp Ther. 1990 Feb;252(2):683-8.

Intravenously administered 5-HT and the 5-HT3 selective agonist, 2CH3-5-HT, and the 5-HT2 selective agonist, alpha-CH3-5-HT, transiently increased heart rate in conscious, instrumented dogs. 5-HT, alpha-CH3-5-HT and 2CH3-5-HT increased systolic blood pressure in conscious dogs. The increase in blood pressure produced by alpha-CH3-5-HT was blocked by the 5-HT2 selective antagonist, LY53857, supporting a role for vascular 5-HT2 receptors in the pressor response to these amines. In contrast, LY53857 did not antagonize tachycardia produced by 2CH3-5-HT. Furthermore, propranolol also did not block 2CH3-5-HT-induced tachycardia, indicating that an indirect neuronal effect to release norepinephrine cannot explain the increase in heart rate to 2CH3-5-HT. Tachycardia to 2CH3-5-HT (as well as to isoproterenol) was modestly inhibited, but never abolished by interruption of the autonomic nervous system with atropine or hexamethonium. 5-HT3 receptor antagonists, zacopride, ICS 205-930 and GR38032F, dose-dependently blocked the tachycardia and pressor response to 2CH3-5-HT. These data establish the presence of a 5-HT3 receptor mediating a direct positive chronotropic effect of 5-HT in conscious dogs, an effect that depends, only minimally, on the presence of an intact autonomic nervous system.

2-Methyl-5-HT hydrochloride (2-Methyl-5-hydroxytryptamine hydrochloride) is a potent and selective 5-HT3 receptor agonist. 2-Methyl-5-HT hydrochloride is shown to display anti-depressive-like effects.

2-Methyl-5-hydroxytryptamine hydrochloride,845861-49-6,Natural Products,5-HT Receptor, buy 2-Methyl-5-hydroxytryptamine hydrochloride , 2-Methyl-5-hydroxytryptamine hydrochloride supplier , purchase 2-Methyl-5-hydroxytryptamine hydrochloride , 2-Methyl-5-hydroxytryptamine hydrochloride cost , 2-Methyl-5-hydroxytryptamine hydrochloride manufacturer , order 2-Methyl-5-hydroxytryptamine hydrochloride , high purity 2-Methyl-5-hydroxytryptamine hydrochloride