China
Africa
Explore chapters and articles related to this topic
Pharmacological Characterization of 5-Hydroxytryptamine Receptors in the Gastrointestinal Tract
Published in T.S. Gaginella, J.J. Galligan, SEROTONIN and GASTROINTESTINAL FUNCTION, 2020
Jeremy D. Gale, Keith T. Bunce
As previously mentioned, the 5-HT2B receptor is the current nomenclature for the receptor mediating the contraction elicited by 5-HT in the rat gastric fundus.83,84 In this preparation, 5-HT is an agonist with high potency (EC50 = 87 nM).61 Other agonists at this receptor include MK-212 (full agonist, 100-fold weaker than 5-HT) and quipazine (partial agonist, 100-fold weaker than 5-HT). However, both quipazine and MK-212 have agonist and/or antagonist activity at a wide range of other 5-HT receptors. The response to 5-HT can be antagonized competitively by yohimbine (pA2 = 8.5) and rauwolscine (pA2 = 8.5),61 both these drugs are classically regarded as being relatively selective for α2-adrenoceptors. Furthermore, the effects of 5-HT can be blocked noncompetitively by LY 53857, methysergide, and metergoline.61 Recently, a competitive antagonist at this receptor has been described, SB 200646 (pA2 = 7.5).85 This compound does not discriminate between 5-HT2B and 5-HT2C receptors, but has 100-fold selectivity over other receptor subtypes.
Antipsychotic Drugs
Published in Sahab Uddin, Rashid Mamunur, Advances in Neuropharmacology, 2020
Harleen Kaur, Ramneek Kaur, Varsha Rani, Kanishka Sharma, Pawan Kumar Maurya
Serotonergic effects of lysergic acid diethylamide are inhibited by clozapine and it also blocks the social effect of quipazine which is a 5-HT agonist (Glennon and Dukat, 2002). This is the proof that this drug is a serotonin antagonist (5-HT). It has also been discovered that clozapine inhibits hormone stimulating effect which is produced by MK-212 due to secretion of cortisol, as well as the hyperthermic effects. The treatment of this drug inhibits induced MK-212 increased secretion of plasma cortisol and therefore, its area under the curve in sufferers appeared to be less as compared to neuroleptic and nonmedicated patients. Thus, chlorpromazine inhibits induction of MK-212 cortisol like clozapine drug does but it is expected that clozapine is more effective and efficient in vivo than chlorpromazine as a 5-HT2 antagonist on the foundation of data for in vitro affinity (Abidi and Bhaskara, 2003). Otherwise, a response seen in a man due to induction of MK-212 cortisol is because of stimulation of receptor 5-HT of some other type which is not inhibited by chlorpromazine but is by clozapine.
Neurobiological Substrates Mediating the Reinforcing Effects of Psychomotor Stimulant and Opiate Drugs
Published in Edythe D. London, Imaging Drug Action in the Brain, 2017
Carol B. Hubner, George F. Koob
Several studies have examined the importance of serotonin in mediating the reinforcing effects of psychomotor stimulant drugs. One experimental approach has been to increase serotonin neurotransmission and evaluate changes in rates of responding maintained by cocaine or amphetamine. Various methods have been used to elevate central serotonin levels. They include administration of the serotonin precursor, L-tryptophan (Lyness, 1983; Smith et al., 1986; Carroll et al., 1990a), pretreatment with serotonergic agonists, including fluoxetine, a serotonin uptake blocker (Leccese and Lyness, 1984; Yu et al., 1986; Carroll et al., 1990b), and administration of quipazine, a direct serotonin receptor agonist (Leccese and Lyness, 1984).
5-HT1A receptor ligands and their therapeutic applications: review of new patents
Published in Expert Opinion on Therapeutic Patents, 2018
Jakub Staroń, Ryszard Bugno, Adam S. Hogendorf, Andrzej J. Bojarski
Researchers at University Laval (Canada) studied the effects of 5-HT1AR agonist administration on the induction or facilitation of urination and defecation in subjects with a spinal cord injury (SCI) [78,79]. An SCI leads to an irreversible loss of sensation and voluntary motor control below the level of injury, associated with bowel and bladder control problems. Researchers tested individual or combinatorial p.o. or s.c. administration of a 5-HT1AR agonist (buspirone), 5-HT1A/7R agonist (e.g. 8-OH-DPAT), 5-HT2/3R agonist (e.g. quipazine), cholinesterase inhibitor (e.g. neostigmine), NMDA agonist (e.g. N-methyl D-aspartate), and noradrenaline/dopamine precursor (e.g. L-DOPA). The combination of buspirone and neostygmine proved to be the most efficacious in inducing the amount of fecal pellets in mice with SCI. A similar efficacy was reported for the coadministration of clenbuterol, quipazine, and 8-OH-DPAT. In the case of urination, the combination of buspirone and 8-OH-DPAT increased the amount of urine 13-fold compared with water vehicle.