Azapirones are a class of drugs used as anxiolytics, antidepressants, and antipsychotics. They are commonly used as add-ons to other antidepressants, such as selective serotonin reuptake inhibitors (SSRIs).
4-Fluoroamphetamine, also known as para-fluoroamphetamine (PFA) is a psychoactive research chemical of the phenethylamine and substituted amphetamine chemical classes. It produces stimulant and entactogenic effects. As a recreational drug, 4-FA is sometimes sold along with related compounds such as 2-fluoroamphetamine and 4-fluoromethamphetamine.
Fludiazepam, marketed under the brand name Erispan (エリスパン) is a potent benzodiazepine and 2ʹ-fluoro derivative of diazepam, originally developed by Hoffman-La Roche in the 1960s. It is marketed in Japan and Taiwan. It exerts its pharmacological properties via enhancement of GABAergic inhibition. Fludiazepam has 4 times more binding affinity for benzodiazepine receptors than diazepam. It possesses anxiolytic, anticonvulsant, sedative, hypnotic and skeletal muscle relaxant properties. Fludiazepam has been used recreationally.
Lofentanil is one of the most potent opioid analgesics known and is an analogue of fentanyl, which was developed in 1960. It is most similar to the highly potent opioid carfentanil (4-carbomethoxyfentanyl), only slightly more potent. Lofentanil can be described as 3-methylcarfentanil, or 3-methyl-4-carbomethoxyfentanyl. While 3-methylfentanyl is considerably more potent than fentanyl itself, lofentanil is only slightly stronger than carfentanil. This suggests that substitution at both the 3 and 4 positions of the piperidine ring introduces steric hindrance which prevents μ-opioid affinity from increasing much further. As with other 3-substituted fentanyl derivatives such as ohmefentanyl, the stereoisomerism of lofentanil is very important, with some stereoisomers being much more potent than others.
Neurotensin receptor type 2 is a protein that in humans is encoded by the NTSR2 gene.
Eseroline is a drug which acts as an opioid agonist. It is a metabolite of the acetylcholinesterase inhibitor physostigmine but unlike physostigmine, the acetylcholinesterase inhibition produced by eseroline is weak and easily reversible, and it produces fairly potent analgesic effects mediated through the μ-opioid receptor. This mixture of activities gives eseroline an unusual pharmacological profile, although its uses are limited by side effects such as respiratory depression and neurotoxicity.
N-n-Propylnorapomorphine (NPA) is an aporphine derivative dopamine agonist closely related to apomorphine. In rodents it has been shown to produce hyperactivity, stereotypy, hypothermia, antinociception, and penile erection, among other effects. Notably, its effects on locomotion are biphasic, with low doses producing inhibition and catalepsy and high doses resulting in enhancement of activity. This is likely due to preferential activation of D2/D3 autoreceptors versus postsynaptic receptors, the latter of which overcomes the former to increase postsynaptic dopaminergic signaling only with high doses.
SC-17599 is a steroid derivative drug discovered in 1968 which acts as a selective μ-opioid receptor agonist, with little or no affinity for the δ-opioid or κ-opioid receptors. It is an active analgesic in vivo, more potent than codeine or pethidine but slightly less potent than morphine, and produces similar effects to morphine in animals but with less sedation
Spiradoline (U-62066) is a drug which acts as a highly selective κ-opioid agonist. It has analgesic, diuretic, and antitussive effects, and produces subjective effects in animals similar to those of ketazocine and alazocine. The main effect in humans is sedation, along with analgesic and diuretic effects, but significant side effects such as dysphoria and hallucinations have stopped it from being used clinically.
MDAI (5,6-methylenedioxy-2-aminoindane) is a drug developed in the 1990s by a team led by David E. Nichols at Purdue University. It acts as a non-neurotoxic and highly selective serotonin releasing agent (SSRA) in vitro and produces entactogen effects in humans.
UH-232 ((+)-UH232) is a drug which acts as a subtype selective mixed agonist-antagonist for dopamine receptors, acting as a weak partial agonist at the D3 subtype, and an antagonist at D2Sh autoreceptors on dopaminergic nerve terminals. This causes dopamine release in the brain and has a stimulant effect, as well as blocking the behavioural effects of cocaine. It may also serve as a 5-HT2A receptor agonist, based on animal studies. It was investigated in clinical trials for the treatment of schizophrenia, but unexpectedly caused symptoms to become worse.
ZK-93423 is an anxiolytic drug from the β-Carboline family, closely related to abecarnil. It is a nonbenzodiazepine GABAA agonist which is not subtype selective and stimulates α1, α2, α3, and α5-subunit containing GABAA receptors equally. It has anticonvulsant, muscle relaxant and appetite stimulating properties comparable to benzodiazepine drugs. ZK-93423 has also been used as a base to develop new and improved beta-carboline derivatives and help map the binding site of the GABAA receptor.
A-68930 is a synthetic compound that acts as a selective dopamine receptor D1 agonist. It is orally active and has antidepressant and anorectic effects in animals, producing wakefulness and tachycardia, but without stimulant effects, instead producing sedation. The difference in effects between A-68930 and other D1 agonists such as SKF-82958 may be due to their differing effects on the related D5 receptor.
Pitrazepin is a competitive GABAA and glycine receptor antagonist. It has been used to study insect and snail nervous systems in scientific research.
5-Benzyloxytryptamine (5-BT), is a tryptamine derivative which acts as an agonist at the 5-HT1D, 5-HT2 and 5-HT6 serotonin receptors, and an antagonist of TRPM8.
ICI-199,441 is a drug which acts as a potent and selective κ-opioid agonist, and has analgesic effects. It is a biased agonist of the KOR, and is one of a relatively few KOR ligands that is G protein-biased rather than β-arrestin-biased.
Hemorphin-4 is an endogenous opioid peptide of the hemorphin family which possesses antinociceptive properties and is derived from the β-chain of hemoglobin in the bloodstream. It is a tetrapeptide with the amino acid sequence Tyr-Pro-Trp-Thr. Hemorphin-4 has affinities for the μ-, δ-, and κ-opioid receptors that are in the same range as the structurally related β-casomorphins, although affinity to the κ-opioid receptor is markedly higher in comparison. It acts as an agonist at these sites. Hemorphin-4 also has inhibitory effects on angiotensin-converting enzyme (ACE), and as a result, may play a role in the regulation of blood pressure. Notably, inhibition of ACE also reduces enkephalin catabolism.
Hemorphins are a class of naturally occurring, endogenous opioid peptides which are found in the bloodstream, and are derived from the β-chain of hemoglobin. They have antinociceptive effects via activation of the opioid receptors, and some may also play a role in blood pressure through inhibition of the angiotensin-converting enzyme (ACE), as well as cause an elevation of endogenous enkephalin levels. Some examples of hemorphins include hemorphin-4, spinorphin, and valorphin.
YM-31636 is a potent and selective 5-HT3 agonist. Systemic administration of YM-31636 increased the number of fecal pellets in rats, and improves colonic motility. It also increases colonic secretions, but not to the point of inducing diarrhea. In addition, it did not reduce the visceral pain threshold, or increase the intensity of visceral pain. These properties indicate that it could be a useful treatment for constipation.
HA-966 or (±) 3-Amino-1-hydroxy-pyrrolidin-2-one is a molecule used in scientific research as a glycine receptor and NMDA receptor antagonist / low efficacy partial agonist. It has neuroprotective and anticonvulsant, anxiolytic, antinociceptive and sedative / hypnotic effects in animal models. Pilot human clinical trials in the early 1960s showed that HA-966 appeared to benefit patients with tremors of extrapyramidal origin.
