Epinephrine is a sympathomimetic catecholamine. It acts as a naturally occurring agonist at both alpha and beta-adrenergic receptors. Three pharmacologic types have been identified: alpha 1-, alpha 2-, and beta-adrenergic receptors. Each of these has three subtypes, characterized by both structural and functional differences. The alpha 2 and beta receptors are coupled negatively and positively, respectively, to adenylyl cyclase via Gi or Gs regulatory proteins, and the alpha 1 receptors modulate phospholipase C via the Go protein. Subtype expression is regulated at the level of the gene, the mRNA, and the protein through various transcriptional and postsynthetic mechanisms. Through its action on alpha-adrenergic receptors, epinephrine lessens the vasodilation and increased vascular permeability that occurs during anaphylaxis, which can lead to loss of intravascular fluid volume and hypotension. Through its action on beta-adrenergic receptors, epinephrine causes bronchial smooth muscle relaxation and helps alleviate bronchospasm, wheezing and dyspnea that may occur during anaphylaxis. Epinephrine also alleviates pruritus, urticaria, and angioedema and may relieve gastrointestinal and genitourinary symptoms associated with anaphylaxis because of its relaxer effects on the smooth muscle of the stomach, intestine, uterus and urinary bladder. Epinephrine increases glycogenolysis, reduces glucose up take by tissues, and inhibits insulin release in the pancreas, resulting in hyperglycemia and increased blood lactic acid.

Epinephrine is a sympathomimetic catecholamine. It acts as a naturally occurring agonist at both alpha and beta-adrenergic receptors. Three pharmacologic types have been identified: alpha 1-, alpha 2-, and beta-adrenergic receptors. Each of these has three subtypes, characterized by both structural and functional differences. The alpha 2 and beta receptors are coupled negatively and positively, respectively, to adenylyl cyclase via Gi or Gs regulatory proteins, and the alpha 1 receptors modulate phospholipase C via the Go protein. Subtype expression is regulated at the level of the gene, the mRNA, and the protein through various transcriptional and postsynthetic mechanisms. Through its action on alpha-adrenergic receptors, epinephrine lessens the vasodilation and increased vascular permeability that occurs during anaphylaxis, which can lead to loss of intravascular fluid volume and hypotension. Through its action on beta-adrenergic receptors, epinephrine causes bronchial smooth muscle relaxation and helps alleviate bronchospasm, wheezing and dyspnea that may occur during anaphylaxis. Epinephrine also alleviates pruritus, urticaria, and angioedema and may relieve gastrointestinal and genitourinary symptoms associated with anaphylaxis because of its relaxer effects on the smooth muscle of the stomach, intestine, uterus and urinary bladder. Epinephrine increases glycogenolysis, reduces glucose up take by tissues, and inhibits insulin release in the pancreas, resulting in hyperglycemia and increased blood lactic acid.

Epinephrine is a sympathomimetic catecholamine. It acts as a naturally occurring agonist at both alpha and beta-adrenergic receptors. Three pharmacologic types have been identified: alpha 1-, alpha 2-, and beta-adrenergic receptors. Each of these has three subtypes, characterized by both structural and functional differences. The alpha 2 and beta receptors are coupled negatively and positively, respectively, to adenylyl cyclase via Gi or Gs regulatory proteins, and the alpha 1 receptors modulate phospholipase C via the Go protein. Subtype expression is regulated at the level of the gene, the mRNA, and the protein through various transcriptional and postsynthetic mechanisms. Through its action on alpha-adrenergic receptors, epinephrine lessens the vasodilation and increased vascular permeability that occurs during anaphylaxis, which can lead to loss of intravascular fluid volume and hypotension. Through its action on beta-adrenergic receptors, epinephrine causes bronchial smooth muscle relaxation and helps alleviate bronchospasm, wheezing and dyspnea that may occur during anaphylaxis. Epinephrine also alleviates pruritus, urticaria, and angioedema and may relieve gastrointestinal and genitourinary symptoms associated with anaphylaxis because of its relaxer effects on the smooth muscle of the stomach, intestine, uterus and urinary bladder. Epinephrine increases glycogenolysis, reduces glucose up take by tissues, and inhibits insulin release in the pancreas, resulting in hyperglycemia and increased blood lactic acid.

Eticlopride {2S(−)-3-chloro-5-ethyl-N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-hydroxy-2-methoxybenzamide} is an antagonist at dopamine D2 and D3 receptors. It is widely used for in vivo, in vitro, and ex vivo examination of D2/D3 receptors densities and function. Eticlopride exerts antipsychotic activity in animals.

Sonepiprazole exhibits highly specific binding to the D4 dopamine receptor with more than 100-fold selectivity for the D4 receptor over other receptors, including dopamine, serotonin, and adrenergic receptors. It is a neutral antagonist at the D4 dopamine receptor and is devoid of dopamine agonist activity. Sonepiprazole selectively induces c-fos expression in the prefrontal cortex and blocks behavioral, biochemical, and genomic effects of repeated amphetamine administration in rats. Sonepiprazole was investigated as an antipsychotic for the treatment of schizophrenia in a placebo-controlled clinical trial, but in contrast to its comparator olanzapine no benefits were found and it was not researched further for this indication.

Aplindore (DAB-452) is a small molecule that displays potent dopamine D2 receptor partial agonist activity in in vitro and in vivo assays and is predicted to have antipsychotic efficacy without motor side effects. Aplindore had been in phase II clinical trials for the treatment of Parkinson's disease and restless legs syndrome. Aplindore was generally well tolerated and there were no withdrawals due to adverse events and no serious adverse events.

Quinpirole (LY 171,555) is a psychoactive drug and research chemical which acts as a selective D2 and D3 receptor agonist. Quinpirole is the most widely used D2 agonist in in vivo and in vitro studies. Specific quinpirole binding in rat brain was saturable, and dependent on temperature, membrane concentration, sodium concentration and guanine nucleotides. Saturation analysis revealed high affinity binding characteristics (KD = 2.3 nM) which were confirmed by association-dissociation kinetics. The regional distribution of [3H]quinpirole binding sites roughly paralleled the distribution of [3H]spiperone binding sites, with greatest densities present in the striatum, nucleus accumbens and olfactory tubercles. A variety of drugs, most notably monoamine oxidase inhibitors (MAOls), inhibit the binding of [3H]quinpirole, but not [3H]spiperone or [3H](-)N-n-Propylnorapomorphine, in rat striatal membranes by a mechanism that does not appear to involve the enzymatic activity of MAO. Clinically antidepressant MAOIs exhibited selectivity between sites labeled by [3H]quinpirole and [3H]spiperone as did a number of structurally related propargylamines and N-acylethylenediamine derivatives and other drugs such as debrisoquin and phenylbiguanide. Quinpirole has been shown to increase locomotion and sniffing behavior in mice and induces compulsive behavior symptomatic of obsessive compulsive disorder in rats.