A natural alkaloid that acts as a selective and reversible α2-adrenergic receptor antagonist (Ki = 12 nM); also acts as a receptor antagonist at the serotonin 5-HT2B receptor (Ki = 14.3 nM).

A cell-permeable mycotoxin which binds to the barbed end of actin, reversibly inhibiting the elongation and shortening of actin filaments; blocks diverse cellular functions, including cell division, migration, phagocytosis, exocytosis, chemotaxis, and glucose transport.

A muscarinic M1 and M2 mACh receptor agonist (pKB = 5 and 3.7, respectively) that is typically used as an animal model for temporal lobe epilepsy.

A cytotoxic, quinoline alkaloid that inhibits the DNA enzyme topoisomerase I (Top I) by binding the Top1-DNA cleavage complex and inducing DNA-strand breaks; has strong anti-tumor activity and induces DNA damage at concentrations as low as 51 nM in whole cells and 12 nM in isolated nuclei in in…

An analog of folic acid and aminopterin that is used in the treatment of cancer, autoimmune diseases, ectopic pregnancy, and for the induction of medical abortions; induces adenosine release, inhibits the metabolism of folic acid, and blocks key enzymes in the synthesis of purines and pyrimidines…

A cell-permeable inhibitor that binds actin filaments, but not actin monomers, to inhibit polymerization at concentrations as low as 0.2 µM.

Inhibits microtubule polymerization (IC₅₀ =3.2 μM) by binding to tubulin, which disrupts spindle formation during mitosis; blocks the growth of MCF-7 human breast carcinoma cells (IC₅₀ = 13 nM); inhibits neutrophil motility and activity (5 μmol/kg in a mouse model of…

Non-selective, competitive antagonist of the muscarinic acetylcholine receptor types M1, M2, M3, M4, and M5 (pKBs range from 8.9-9.8); increases firing of the sinoatrial node and conduction through the atrioventricular node of the heart, opposes the actions of the vagus nerve, blocks acetylcholine…

A natural 11-membered macrocyclic pyrrolizidine alkaloid used in an animal model of pulmonary hypertension.

Inhibits actin polymerization; uniquely inhibits HIV-1 protease (IC50 = 3 μM); rapidly and reversibly inhibits glucose transport by competitively binding glucose transporters (Ki = 4.0 μM); induces the phosphorylation of the tyrosine phosphatase PTP3 of Dictyostelium, activating STATc.

A full GABAA agonist and partial GABAC agonist; binds GABAA on both high- and low-affinity sites (Kd = 10 and 270 nM, respectively), stimulating chloride efflux with an EC50 of 200 nM; activates GABAC receptors with an EC50 of 1.3 μM; impairs memory formation and retrieval; attenuates airway constriction.

A cell-permeable inhibitor of actin polymerization that has been shown to be 10 times less toxic in mice than cytochalasin D.

A natural sesquiterpene alkaloid that inhibits AChE in rat cortex in vitro (IC₅₀ = 82 nM) and displays oral AChE inhibitory activity in animals.