A molecular pharmacology diagram illustrating the conformational switch of the Cannabinoid Receptor 2 (CB2R) between active (left) and inactive (right) states. The visual depicts a G protein-coupled receptor (GPCR) model featuring alpha-helical transmembrane domains. The central mechanism shown is the 'toggle switch' involving the Trp258 residue within a 'secondary site/toggle pocket'. On the left, the agonist HU-308 binds to the primary site, leaving Trp258 in an upright active conformation. On the right, a modified ligand stabilizes the inactive state through a stereogenic phenyl group that engages in an edge-to-face pi-interaction with Trp258, effectively 'switching off' receptor signaling. Key molecular modifications to the ligand for therapeutic development are highlighted: 1) fluorophore conjugation for imaging, 2) stereogenic phenyl group for functional inactivation (e.g., inhibiting beta-arrestin association and ERK1/2 phosphorylation), 3) azide incorporation for improved affinity, and 4) a novel resorcinol moiety. The diagram highlights structural biology concepts in drug design, specifically targeting the active/inactive equilibrium of GPCRs for pain modulation research.

This pathophysiology diagram illustrates the role of the Beta-2 Adrenergic Receptor (ADRB2) in modulating inflammatory responses during Rhinovirus (RV) infection. The visual is divided into three primary sections: [1] depicts RV particles binding to Intercellular Adhesion Molecule 1 (ICAM-1) on the surface of airway epithelial cells (ECs). [2] demonstrates that ADRB2 activation inhibits the expression of ICAM-1 and the subsequent release of cytokines and chemokines from these epithelial cells. [3] focuses on systemic immune cell modulation, showing that ADRB2 signaling exerts inhibitory effects (indicated by red T-bars) on multiple cell types: in macrophages (Mφ), it suppresses TNF-α, IL-6, IL-1β, and various CCL chemokines; in mast cells (MC), it inhibits TNF-α, histamine, and leukotriene release; in CD4+ T cells, it suppresses IFN-γ production; and in CD8+ T cells, it blocks TNF-α, IFN-γ, and cytolytic activity. The diagram serves as an educational resource for understanding neuro-immune interactions and the therapeutic mechanism of beta-agonists in dampening virus-induced airway inflammation.

This pathophysiology diagram summarizes the influence of Peroxisome Proliferator-Activated Receptor (PPAR) ligands on breast carcinogenesis. The central mechanism illustrates unligated PPAR-delta inhibiting PPAR-alpha and PPAR-gamma while transitioning to an active ligated PPAR-delta state. The diagram compares the cellular effects of three PPAR isoforms. PPAR-alpha (left, gray box) is linked to potential antiproliferative, antiangiogenic, and anti-immortalizing effects, but is noted as carcinogenic in the liver. PPAR-delta (center, pink box) is associated with proproliferative and proangiogenic activities, labeled with the caveat 'More data warranted.' PPAR-gamma (right, green box) demonstrates predominantly antitumorigenic properties, including pro-apoptotic, anti-invasive, and anti-immortalizing effects, as well as TGF-beta suppression; its antiproliferative action is noted as concentration-dependent. The illustration uses schematic cell clusters to represent tumor progression or regression, with a crossed-out cluster over the PPAR-gamma pathway indicating therapeutic potential. This resource is intended for advanced medical education in oncology and molecular pharmacology.