Pamoic acid, also called embonic acid, is a naphthoic acid derivative, used as a counter ion of a drug compound to increase the solubility of the drug in water. Pamoic acid has agonist activity for the orphan G protein-coupled receptor GPR35 by which it activates ERK and beta-arrestin2, and causes antinociceptive activity. Although (like other drug salts) it has been considered an inactive compound by the FDA.

Domoic acid is one of the best-known marine toxins, causative of important neurotoxic alterations. In the year 1987, domoic acid was responsible for four deaths and the illness of more than 100 people after consuming blue mussels (Mytilus edulis) harvested in the Cardigan Bay of Prince Edward Island, Canada. The symptomatology comprised three kinds of signs: gastrointestinal (nausea, vomiting,), cardiovascular (unstable blood pressure and arrhythmias), and neurological signs (disorientation, confusion, hallucinations, coma, and memory impairment). After this event was discovered the domoic acid epileptic. Nearly a year after the amnesic shellfish poisoning event, an 84 years old male survivor re-experienced severe seizures and was diagnosed with temporal lobe epilepsy caused by domoic acid intoxication. This toxin has a high affinity for the glutamate receptors (GluRs) subtypes: alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and KA receptors. The binding of domoic acid to receptors provokes an increase of calcium (Ca2+) levels, causing the release of Glu to the extracellular space, and the activation of N-methyl-d-aspartate (NMDA) receptors. The histological consequences of these cellular alterations comprise astrocytosis, cytoskeletal disarrangement and, finally, cell death.

Dermorphin is a selective mu-opioid receptor agonist. It was isolated from isolated from skin extracts of frogs belonging to the genus Phyllomedusa and was shown to relife pain in patients with postoperative pain syndrome.

4-(M-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium (McN-A-343) is a selective muscarinic M1 receptors agonist, which leads to its widespread use as an aid to distinguish responses mediated through M₁ receptors from those utilizing M₂ or M₃ muscarinic receptor subtypes, especially in the CNS. McN-A-343 has a number of non-muscarinic actions. These include activation of some types of nicotinic acetylcholine receptors, antagonism of serotonin 5-HT₃ and 5-HT₄ receptor subtypes, inhibition of the uptake mechanism and a local anesthetic action.

Poppy acid occurs in opium (Papaver somniferum) and other Papaver species. Meconic acid has been described as a mild narcotic, but it has little or no physiological action, and is not now used medicinally. Its chemical reactions are of importance in toxicology as a valuable indication of the presence of opium.

Hordenine is a natural Phenethylamine compound that occurs in a number of different plants, but especially barley grass. It is structurally similar to the amino acid Tyramine. It antagonized D2-mediated beta-arrestin recruitment indicating functional selectivity. Hordenine inhibited melanogenesis by suppressing cAMP production, which is involved in the expression of melanogenesis-related proteins. Hordenine may be an effective inhibitor of hyperpigmentation. Hordenine is an indirectly acting adrenergic drug. It liberates norepinephrine from stores. In isolated organs and those structures with reduced epinephrine contents, the hordenine-effect is only very poor. Experiments in intact animals (rats, dogs) show that hordenine has a positive inotropic effect upon the heart, increases systolic and diastolic blood pressure, peripheral blood flow volume, inhibits gut movements but has no effect upon the psychomotorical behavior of mice. Hordenine is considered to be generally very safe and well-tolerated in healthy adults. Hordenine is a nootropic compound that works equally well for cognitive enhancement and athletic performance.

Gramine (aka donaxine) is a naturally occurring indole alkaloid that can be found in several plant species. It is toxic to many organisms and may be a natural defense mechanism for these plants. Gramine has been found to act as an agonist of the adiponectin receptor 1 (AdipoR1) which plays an important role in the suppression of metabolic disorders that can result in type 2 diabetes, obesity, and atherosclerosis.

D-alanine is an isomer of non-essential L-amino acid. D isomer is found in the cell walls of bacteria, but not in bacterial proteins. It was discovered, that being an endogenous agonist of the glycine site of the N-methyl-d-aspartate (NMDA) receptor, D-alanine can have beneficial effects on schizophrenia.