Pathways

Meclofenamic acid is a nonsteroidal anti-inflammatory (NSAID) with antipyretic and antigranulation activities. It also inhibits prostaglandin biosynthesis. It is used for the treatment of mild to moderate pain. It targets the prostaglandin G/H synthase-1 (COX-1) and prostaglandin G/H synthase-2 (COX-2) in the cyclooxygenase pathway. The cyclooxygenase pathway begins in the cytosol with phospholipids being converted into arachidonic acid by the action of phospholipase A2. The rest of the pathway occurs on the endoplasmic reticulum membrane, where prostaglandin G/H synthase 1 & 2 convert arachidonic acid into prostaglandin H2. Prostaglandin H2 can either be converted into thromboxane A2 via thromboxane A synthase, prostacyclin/prostaglandin I2 via prostacyclin synthase or prostaglandin E2 via prostaglandin E synthase. COX-2 is an inducible enzyme, and during inflammation, it is responsible for prostaglandin synthesis. It leads to the formation of prostaglandin E2 which is responsible for contributing to the inflammatory response by activating immune cells and for increasing pain sensation by acting on pain fibers. Meclofenamic acid inhibits the action of COX-1 and COX-2 on the endoplasmic reticulum membrane. This reduces the formation of prostaglandin H2 and therefore, prostaglandin E2 (PGE2). The low concentration of prostaglandin E2 attenuates the effect it has on stimulating immune cells and pain fibers, consequently reducing inflammation and pain. Moreover, in vitro, meclofenamic acid was found to be an inhibitor of human leukocyte 5-lipoxygenase activity; that may be responsible for the anti-inflammatory action of this drug. Meclofenamic acid is administered as an oral capsule.

Mirabegron is a beta-3 adrenergic receptor agonist that is used to treat overactive bladder and neurogenic detrusor activity. It relaxes the smooth muscle of the bladder which expands the bladder to relieve urgency. It is an oral medication that lacks significant antimuscarinic activity to reduce adverse effects in comparison to other drugs used for overactive bladder treatment. Mirabegron can be found under the brand name Myrbetriq and allows for the relaxation of detrusor smooth muscle of the bladder during the storage phase of the urinary bladder fill-void cycle via the activation of adenylyl cyclase. Once Mirabegron is administered and it binds to the beta-3 adrenergic receptor, the G protein signalling cascade begins. The alpha and beta/gamma subunits of the G protein separate and GDP is replaced with GTP on the alpha subunit. This alpha subunit then activates adenylyl cyclase which converts ATP to cAMP. cAMP then activates protein kinase A (PKA) which in turn phosphorylates targets and inhibits MLCK through decreased calcium levels causing muscle relaxation. PKA can phosphorylate certain Gq-coupled receptors as well as phospholipase C (PLC) and thereby inhibit G protein-coupled receptor (GPCR) -PLC-mediated phosphoinositide (PI) generation, and thus calcium flux. PKA phosphorylates the inositol 1,4,5-trisphosphate (IP3) receptor to reduce its affinity for IP3 and further limit calcium mobilization. PKA phosphorylates myosin light chain kinase (MLCK) and decreases its affinity to calcium calmodulin, thus reducing activity and myosin light chain (MLC) phosphorylation. PKA also phosphorylates KCa++ channels in ASM, increasing their open-state probability (and therefore K+ efflux) and promoting hyperpolarization. Since myosine light chain kinase is not activated, Serine/threonine-protein phosphatase continues to dephosphorylate myosin LC-P, and more cannot be synthesized so myosin remains unbound from actin causing muscle relaxation. This relaxation of the smooth muscles in the bladder causes the bladder to expand to relax, making the sense of urgency for urination lesser. Some side effects of using mirabegron may include nausea, constipation, headache, and dizziness.

Racepinephrine is a bronchodilator used to treat asthma. It can be found under the brand name Asthmanefrin and is orally inhaled to act on both alpha and beta adrenergic receptors. This drug has a rapid onset and short duration and acts as a smooth muscle relaxant and constrictor in different tissues. It is a beta-2 adrenergic receptor agonist which allows for the activation of adenylyl cyclase to relax the smooth muscle of the lungs, and it is also an alpha-1 adrenergic receptor agonist which causes smooth muscle constriction of arterioles. Constricting the pre capillary arterioles reduces the hydrostatic pressure and consequently bronchial mucosal edema. Racepinephrine is a racemic mixture consisting of d-Epinephrine and l-Epinephrine enantiomers. Epinephrine is a non-selective α- and β-adrenergic receptor agonist. It is a bronchodilator used in the temporary relief of mild symptoms of intermittent asthma including wheezing, tightness of chest and shortness of breath. It is an active ingredient in oral inhalation over-the-counter products as racepinephrine hydrochloride. Once racepinephrine is administered and it binds to the beta-2 adrenergic receptor, the G protein signalling cascade begins. The alpha and beta/gamma subunits of the G protein separate and GDP is replaced with GTP on the alpha subunit. This alpha subunit then activates adenylyl cyclase which converts ATP to cAMP. cAMP then activates protein kinase A (PKA) which in turn phosphorylates targets and inhibits MLCK through decreased calcium levels causing muscle relaxation. PKA can phosphorylate certain Gq-coupled receptors as well as phospholipase C (PLC) and thereby inhibit G protein-coupled receptor (GPCR) -PLC-mediated phosphoinositide (PI) generation, and thus calcium flux. PKA phosphorylates the inositol 1,4,5-trisphosphate (IP3) receptor to reduce its affinity for IP3 and further limit calcium mobilization. PKA phosphorylates myosin light chain kinase (MLCK) and decreases its affinity to calcium calmodulin, thus reducing activity and myosin light chain (MLC) phosphorylation. PKA also phosphorylates KCa++ channels in ASM, increasing their open-state probability (and therefore K+ efflux) and promoting hyperpolarization. Since myosine light chain kinase is not activated, Serine/threonine-protein phosphatase continues to dephosphorylate myosin LC-P, and more cannot be synthesized so myosin remains unbound from actin causing muscle relaxation. This relaxation of the smooth muscles in the lungs causes the bronchial airways to relax which causes bronchodialation, making it easier to breathe. Side effects of using racepinephrine may include blurred vision, chest pain, and difficulty speaking.

Balsalazide, brand name Colazal, is an aminosalicylate anti-inflammatory drug used in the treatment of mildly to moderately active ulcerative colitis. Balsalazide works by delivering its metabolite 9mesalazine) to the large intestine to act directly on ulcerative colitis. Mesalazine is also known as 5-aminosalicylic acid (5-ASA). Balsalazide disodium is delivered intact to the colon where it is cleaved by bacterial azoreduction. The mechanism of action of 5-aminosalicylic acid is unknown. Like the other NSAIDs, it probably targets the prostaglandin G/H synthase-1 (COX-1) and prostaglandin G/H synthase-2 (COX-2) in the cyclooxygenase pathway. The cyclooxygenase pathway begins in the cytosol with phospholipids being converted into arachidonic acid by the action of phospholipase A2. The rest of the pathway occurs on the endoplasmic reticulum membrane, where prostaglandin G/H synthase 1 & 2 convert arachidonic acid into prostaglandin H2. Prostaglandin H2 can either be converted into thromboxane A2 via thromboxane A synthase, prostacyclin/prostaglandin I2 via prostacyclin synthase, or prostaglandin E2 via prostaglandin E synthase. COX-2 is an inducible enzyme, and during inflammation, it is responsible for prostaglandin synthesis. It leads to the formation of prostaglandin E2 which is responsible for contributing to the inflammatory response by activating immune cells and for increasing pain sensation by acting on pain fibers. Salsalate inhibits the action of COX-1 and COX-2 on the endoplasmic reticulum membrane. This reduces the formation of prostaglandin H2 and therefore, prostaglandin E2 (PGE2). The low concentration of prostaglandin E2 attenuates the effect it has on stimulating immune cells and pain fibers, consequently reducing inflammation and pain. Moreover, it is possible that this drug also inhibits the lipoxygenase pathway (catalyzes the formation of leukotrienes and hydroxyeicosatetraenoic acids from arachidonic acid and its metabolites) by inhibiting the enzyme named arachidonate 5-lipoxygenase.

Vibegron is a beta-3 adrenergic agonist the treatment of overactive bladder (OAB) with symptoms of urge urinary incontinence, urgency, and urinary frequency in adults. It can be found under the brand name Gemtesa and it relaxes the detrusor smooth muscle of the bladder, thereby increasing bladder capacity. β3AR is stimulated and undergoes a conformation change and activates adenylyl cyclases (AC), which promotes the formation of cyclic adenosine monophosphate (cAMP). Increased intracellular cAMP concentration leads to the activation of cAMP-dependent protein kinase A (PKA), which subsequently phosphorylates myosin light chains that are responsible for inhibiting the interaction of actin with myosin dependent on calcium – calmodulin complex. Once vibegron is administered and it binds to the beta-3 adrenergic receptor, the G protein signalling cascade begins. The alpha and beta/gamma subunits of the G protein separate and GDP is replaced with GTP on the alpha subunit. This alpha subunit then activates adenylyl cyclase which converts ATP to cAMP. cAMP then activates protein kinase A (PKA) which in turn phosphorylates targets and inhibits MLCK through decreased calcium levels causing muscle relaxation. PKA can phosphorylate certain Gq-coupled receptors as well as phospholipase C (PLC) and thereby inhibit G protein-coupled receptor (GPCR) -PLC-mediated phosphoinositide (PI) generation, and thus calcium flux. PKA phosphorylates the inositol 1,4,5-trisphosphate (IP3) receptor to reduce its affinity for IP3 and further limit calcium mobilization. PKA phosphorylates myosin light chain kinase (MLCK) and decreases its affinity to calcium calmodulin, thus reducing activity and myosin light chain (MLC) phosphorylation. PKA also phosphorylates KCa++ channels in ASM, increasing their open-state probability (and therefore K+ efflux) and promoting hyperpolarization. Since myosine light chain kinase is not activated, Serine/threonine-protein phosphatase continues to dephosphorylate myosin LC-P, and more cannot be synthesized so myosin remains unbound from actin causing muscle relaxation. This relaxation of the smooth muscles in the bladder causes the bladder to expand to relax, making the sense of urgency for urination lesser. Some side effects of using vibegron may include headache, nausea, fever, and diarrhea.

Olsalazine, also known as Dipentum, is a non-steroidal anti-inflammatory drug (NSAID). It is a prodrug of mesalamine (5-aminosalicylic). This drug comprises 2 mesalamine molecules, they are joined together by an azo bridge that is cleaved by azoreductase-containing bacteria in the colon. Olsalazine is indicated for the maintenance of remission of ulcerative colitis. It targets the prostaglandin G/H synthase-1 (COX-1) and prostaglandin G/H synthase-2 (COX-2) in the cyclooxygenase pathway. The cyclooxygenase pathway begins in the cytosol with phospholipids being converted into arachidonic acid by the action of phospholipase A2. The rest of the pathway occurs on the endoplasmic reticulum membrane, where prostaglandin G/H synthase 1 & 2 convert arachidonic acid into prostaglandin H2. Prostaglandin H2 can either be converted into thromboxane A2 via thromboxane A synthase, prostacyclin/prostaglandin I2 via prostacyclin synthase, or prostaglandin E2 via prostaglandin E synthase. COX-2 is an inducible enzyme, and during inflammation, it is responsible for prostaglandin synthesis. It leads to the formation of prostaglandin E2 which is responsible for contributing to the inflammatory response by activating immune cells and for increasing pain sensation by acting on pain fibers. Mesalazine inhibits the action of COX-1 and COX-2 on the endoplasmic reticulum membrane. This reduces the formation of prostaglandin H2 and therefore, prostaglandin E2 (PGE2). The low concentration of prostaglandin E2 attenuates the effect it has on stimulating immune cells and pain fibers, consequently reducing inflammation and pain. Furthermore, mesalazine also inhibits arachidonate 5-lipoxygenase, diminishing the inflammatory processes (leukotriene biosynthesis) and the peroxisome proliferator-activated receptor gamma (inhibiting transcription factors; NF-kappa-B-mediated proinflammatory responses). Olsalazine is administered as an oral capsule.

Ephedrine is an alpha and beta-adrenergic agonist indicated to treat hypotension under anesthesia, allergic conditions, bronchial asthma, and nasal congestion. It is administered as an intravenous injection, and can be found under the brand names Akovaz, Bronkaid, Corphedra, Emerphed, Primatene, and Rezipres. Ephedrine increases blood pressure by stimulating heart rate and cardiac output and variably increasing peripheral resistance. It causes bronchodilation due to the activation of beta-adrenergic receptors in the lungs. Ephedrine is a direct and indirect sympathomimetic amine. As a direct effect, ephedrine activates alpha-adrenergic and beta-adrenergic receptors. Ephedrine acts as an agonist of alpha-1, beta-1 and beta-2-adrenergic receptors. Ephedrine binds to the beta-2 adrenergic receptor, the G protein signalling cascade begins. The alpha and beta/gamma subunits of the G protein separate and GDP is replaced with GTP on the alpha subunit. This alpha subunit then activates adenylyl cyclase which converts ATP to cAMP. cAMP then activates protein kinase A (PKA) which in turn phosphorylates targets and inhibits MLCK through decreased calcium levels causing muscle relaxation. PKA can phosphorylate certain Gq-coupled receptors as well as phospholipase C (PLC) and thereby inhibit G protein-coupled receptor (GPCR) -PLC-mediated phosphoinositide (PI) generation, and thus calcium flux. PKA phosphorylates the inositol 1,4,5-trisphosphate (IP3) receptor to reduce its affinity for IP3 and further limit calcium mobilization. PKA phosphorylates myosin light chain kinase (MLCK) and decreases its affinity to calcium calmodulin, thus reducing activity and myosin light chain (MLC) phosphorylation. PKA also phosphorylates KCa++ channels in ASM, increasing their open-state probability (and therefore K+ efflux) and promoting hyperpolarization. Since myosine light chain kinase is not activated, Serine/threonine-protein phosphatase continues to dephosphorylate myosin LC-P, and more cannot be synthesized so myosin remains unbound from actin causing muscle relaxation. This smooth muscle relaxation causes the arteries and bronchioles to dilate. Some side effects of using ephedrine may include blurred vision, irregular heartbeat, headache, and tiredness.

Dexibuprofen, or S(+)-ibuprofen, is one of the two active enantiomer of racemic ibuprofen, a non-steroidal anti-inflammatory drug (NSAID). It is used to treat pain and inflammation in many conditions. This drug is available as an oral tablet. Dexibuprofen targets the prostaglandin G/H synthase-1 (COX-1) and prostaglandin G/H synthase-2 (COX-2) in the cyclooxygenase pathway. The cyclooxygenase pathway begins in the cytosol with phospholipids being converted into arachidonic acid by the action of phospholipase A2. The rest of the pathway occurs on the endoplasmic reticulum membrane, where prostaglandin G/H synthase 1 & 2 convert arachidonic acid into prostaglandin H2. Prostaglandin H2 can either be converted into thromboxane A2 via thromboxane A synthase, prostacyclin/prostaglandin I2 via prostacyclin synthase, or prostaglandin E2 via prostaglandin E synthase. COX-2 is an inducible enzyme, and during inflammation, it is responsible for prostaglandin synthesis. It leads to the formation of prostaglandin E2 which is responsible for contributing to the inflammatory response by activating immune cells and for increasing pain sensation by acting on pain fibers. Dexibuprofen inhibits the action of COX-1 and COX-2 on the endoplasmic reticulum membrane. This reduces the formation of prostaglandin H2 and therefore, prostaglandin E2 (PGE2). The low concentration of prostaglandin E2 attenuates the effect it has on stimulating immune cells and pain fibers, consequently reducing inflammation and pain. Fever is triggered by inflammatory and infectious diseases. Cytokines are produced in the central nervous system (CNS) during an inflammatory response. These cytokines induce COX-2 production that increases the synthesis of prostaglandin, specifically prostaglandin E2 which adjusts hypothalamic temperature control by increasing heat production. Because dexibuprofen decreases PGE2 in the CNS, it has an antipyretic effect. Antipyretic effects results in increased peripheral blood flow, vasodilation, and subsequent heat dissipation.

Dexketoprofen is the R(-)-enantiomer of racemic ketoprofen. This drug is an NSAID with analgesic, antipyretic, and anti-inflammatory properties. NSAIDs are used to treat only short-term mold to moderate pain. This drug reduces prostaglandin synthesis via inhibition of cyclooxygenase pathway (both COX-1 and COX-2) activity. The cyclooxygenase pathway begins in the cytosol with phospholipids being converted into arachidonic acid by the action of phospholipase A2. The rest of the pathway occurs on the endoplasmic reticulum membrane, where prostaglandin G/H synthase 1 & 2 convert arachidonic acid into prostaglandin H2. Prostaglandin H2 can either be converted into thromboxane A2 via thromboxane A synthase, prostacyclin/prostaglandin I2 via prostacyclin synthase, or prostaglandin E2 via prostaglandin E synthase. COX-2 is an inducible enzyme, and during inflammation, it is responsible for prostaglandin synthesis. It leads to the formation of prostaglandin E2 which is responsible for contributing to the inflammatory response by activating immune cells and for increasing pain sensation by acting on pain fibers. Dexketoprofen inhibits the action of COX-1 and COX-2 on the endoplasmic reticulum membrane. This reduces the formation of prostaglandin H2 and therefore, prostaglandin E2 (PGE2). The low concentration of prostaglandin E2 attenuates the effect it has on stimulating immune cells and pain fibers, consequently reducing inflammation and pain. Fever is triggered by inflammatory and infectious diseases. Cytokines are produced in the central nervous system (CNS) during an inflammatory response. These cytokines induce COX-2 production that increases the synthesis of prostaglandin, specifically prostaglandin E2 which adjusts hypothalamic temperature control by increasing heat production. Because dexketoprofen decreases PGE2 in the CNS, it has an antipyretic effect. Antipyretic effects result in an increased peripheral blood flow, vasodilation, and subsequent heat dissipation. Dexketoprofen is administered as an oral tablet.

Etafedrine is a beta-2 adrenoceptor agonist used to treat a cough associated with inflamed mucosa. It can be found under the brand name Dalmacol and is a long acting bronchodilator that relaxes the smooth muscle of the lungs. It can be used for treatment of conditions characterized by bronchial congestion and bronchospasm when an expectorant or bronchodilator action is required, such as acute bronchitis, acute episodes of chronic bronchitis and bronchial asthma. Once etafedrine is administered and it binds to the beta-2 adrenergic receptor, the G protein signalling cascade begins. The alpha and beta/gamma subunits of the G protein separate and GDP is replaced with GTP on the alpha subunit. This alpha subunit then activates adenylyl cyclase which converts ATP to cAMP. cAMP then activates protein kinase A (PKA) which in turn phosphorylates targets and inhibits MLCK through decreased calcium levels causing muscle relaxation. PKA can phosphorylate certain Gq-coupled receptors as well as phospholipase C (PLC) and thereby inhibit G protein-coupled receptor (GPCR) -PLC-mediated phosphoinositide (PI) generation, and thus calcium flux. PKA phosphorylates the inositol 1,4,5-trisphosphate (IP3) receptor to reduce its affinity for IP3 and further limit calcium mobilization. PKA phosphorylates myosin light chain kinase (MLCK) and decreases its affinity to calcium calmodulin, thus reducing activity and myosin light chain (MLC) phosphorylation. PKA also phosphorylates KCa++ channels in ASM, increasing their open-state probability (and therefore K+ efflux) and promoting hyperpolarization. Since myosine light chain kinase is not activated, Serine/threonine-protein phosphatase continues to dephosphorylate myosin LC-P, and more cannot be synthesized so myosin remains unbound from actin causing muscle relaxation. This relaxation of the smooth muscles in the lungs causes the bronchial airways to relax which causes bronchodialation, making it easier to breathe. Some side effects of using etafedrine may include blurred vision, headache, and lightheadedness.