Dr. Al-Khrasani Mahmoud, Ph.D Semmelweis Egyetem

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1 Dr. Al-Khrasani Mahmoud, Ph.D Semmelweis Egyetem
FARMAKOLÓGIA ALAPJAI Dr. Al-Khrasani Mahmoud, Ph.D Semmelweis Egyetem

2 ALAP ELVEK Farmakológia (gyógyszertan): az élő rendszerek és a működésüket befolyásoló anyagok (farmakonok) kölcsönhatásaival foglalkozó tudomány. Orvosi gyógyszertan: Tárgya a betegségek megelőzése, diagnosztizálása és gyógyitása. A toxikológia (méregtan) a gyógyszertannak az az ága, amely az anyagoknak a szervezetre gyakorolt káros, nemkívánatos hatásaival foglalkozik.

3 ALAP ELVEK Pharmacon (greece=görög)= drug (angol)  egyaránt jelent gyógyszert, mérget és kábitószert, nem azonos jelentésű a magyar gyógyszer szóval. Drog (magyarul) gyógyszerként használt növényi vagy állat szervet illetve szövetet jelent. A kábitószerek is gyakran drognak nevezik.

4 TERÁPIA ALAPJAI - CURATIVE Antibiotikumok SUPRESSIVE
Stimulative - PREVENTIVE Antibiotikumok Antihipertenzív szerek Oralis antidiabetikum. malaria, anticoncipiensek

5 DROG TERMÉSZETE Természeti, szintetikus és félszintetikus
Agonista, antagonista. Endogén: A szervezetben szintetizálódik (hormonok, transzmitterek) vagy xenobiotikumok (xenos= idegen). Mérgek (Nővényi, állati és fémek: ólom és arzén). Szilárd, folyékony(nikotin) vagy gáz (nitrous oxid) Sorsuk a szervezetben (TRANSZPORTÁLÁS, INAKTIVÁLÁS/ELVÁLASZTÁS)

6 DROG TERMÉSZETE Fizikai tulajdonságok
- Szilárd, folyékony, gáz (meghatározza a beadási módot). Szerves vegyületek ( fehérjék, szénhidrátok, zsírok). - Gyenge savak / bázisok.

7 DROG-SZERVEZET INTERAKCIÓ DROG-RECEPTOR KÖTÉSEK
FARMAKODINÁMIA: a gyógyszer szervezetre kifejtett hatásával, a gyógyszerválasz folyamatával foglalkozó tudomány. FARMAKOKINETIKA: a gyógyszerek szervezeten belüli sorsának jellemzésével foglalkozó tudomány. DROG-RECEPTOR KÖTÉSEK Elektrosztatikus (erős, gyenge (H kötés) és nagyon gyenge (van der Waals : dipol interakció). Kovalens (phenoxybenzamin, alkilazó szerek) Hydrophobos

8 DROG-RECEPTOR INTERAKCIÓ
β A + R AR AR* Válasz K-1 α K+1 B + R BR Nincs válasz K-1 A= Agonista B= Antagonista

9 VÁLASZ kívánatos therapiás Nemkívánatos (mellékhatás, toxikus hatás)
Therapiás Index = LD50 / ED50

10 AGONIST : Az a gyógyszer amikor receptorhoz kötődik, megváltoztatja a receptor aktivitását, és eredményként biológiai választ idézhet elő. Az agonista típusok : - Full (tejes) agonisták - Parciális agonisták (Buprenorphine μ, Pindolol β-receptors) - Keverd agonisták (agonista + antagonista; Nalorphine antagonista μ-on és parciális κ-on )

11 DÓZIS-HATÁS ÖSSZEFÜGGÉSE
100 Teljes agonista 80 Relatív hatékonyság 60 40 Parciális agonista 20 Antagonista 1 2 4 8 16 Koncentráció (nM)

12 Potency Hatás A is erősebb mint a B Agonista A Agonista B (%)
Agonista dózis-hatás összefüggés Agonista A Agonista B 100 100 80 80 (%) 60 60 Hatás 40 40 20 20 1 1 2 4 8 Koncentráció (nM) Potency A is erősebb mint a B

13 Hatás (%) Log Koncentráció (nM) Agonista dózis-hatás összefüggés A B
100 80 60 50 40 EC50 EC50 20 1 2 4 8 16 Log Koncentráció (nM) Relatív hatáserősség (potency)

14 Dózis-hatás összefüggés
Hatáserősség (Potency): EC50 vagy az IC50 (in vitro) és ED50 vagy ID50 (in vivo) alapján határozzuk meg. Hatékonyság (Efficacy): a válasz nagyságában mutatkozik.

15 Az agonista affinitás meghatározására használt elméleti módszer

16 ANTAGONISTA: Receptorokhoz kötődik és nem ídéz elő biológiai választ (kompetitív antagonista).
Az antagonista típusok : - Kompetitív antagonismus - NemKompetitív antagonismus - Fiziológiai antagonizmus (glucocorticoids ↔ Insulin) - Kémiai antagonizmus (Heparine↔ protamin szulfat) - Farmakokinetikai antagonizmus (warfarin↔Phenobarbital)

17 Agonista dózis-hatás összefüggés antagonista nélkül (kékszín) és antagonista jelenlétében (rózsaszín ) Agonist alone Agonist + antagonist 100 100 80 80 (%) 60 60 Hatás 40 40 20 20 1 2 4 8 Koncentráció

18 Hatás (%) Log Koncentráció (nM)
Agonista dózis-hatás összefüggés antagonista nélkül A és antagonista jelenlétében Á Hatás (%) A Á 100 80 60 50 40 EC50 20 EC’50 1 2 4 8 16 Log Koncentráció (nM) (antagonista konc.) DR= EC’50 EC50 DR-1= Ke Ke: disszociációs konstans

19 Dózis-hatás összefüggés ábrázolása
Fokozatos Null dózis-hatás görbék Kummalatív dózis-hatás görbék - Kvantális

20 Graded dose-response curves for four drugs, illustrating different pharmacologic potencies and different maximal efficacies.

21 Quantal dose-effect plots
Quantal dose-effect plots. Shaded boxes (and the accompanying curves) indicate the frequency distribution of doses of drug required to produce a specified effect; ie, the percentage of animals that required a particular dose to exhibit the effect. The open boxes (and the corresponding curves) indicate the cumulative frequency distribution of responses, which are lognormally distributed.

22 A GYÓGYSZEREK TÁMADÁSPONTJA
FEHÉRJE: - RECEPTOROK (INTRACELLULÁRIS VAGY MEMBRÁNRECEPTOR) - ENZIMEK - IONCSATORNÁK TRANSZPORTFEHÉRJE MIKROORGANIZMUSANYAGCSEREFEHÉJE

23 Fulvestrant breast cancer in postmenopausal women
RECEPTOR AGONISTA ANTAGONISTA Nicotine ACh receptor Acetylcholine Nicotine Tubocurarine α-Bungarotoxine β-adrenoceptor NE, Isoprenaline Propranolol Opioid (μ-receptor) Morphine, DAMGO Naloxone, Naltrexone Oestrogen receptor Ethinylestradiol Fulvestrant breast cancer in postmenopausal women

24 ION CHANNELS BLOCKERS MODULATORS Voltage-gated Na channels
Local anaesthetics Tetrodotoxin Veratridine Renal tubule Na channels Amiloride Aldosterone Voltage-gated Ca-channel Divalent cations Cd2+ Dihydropyridines Voltage-gated K channels 4-Aminopyridine ATP-sensitive K channels ATP Cromakalim Sulphonylureas GABA-gated chloride channels Picrotoxin Benzodiazepines

25 ENZYMES INHIBITORS FALSE SUBSTRATES Acetylcholinestrase Neostigmine Organophosphate Choline acetyltransferase Hemicholine Cyclooxygenase Asprine Dopa decarboxylase Carbidopa Methyldopa Thymidine kinase Aciclovir HIV protease Saquinavir Revers transcriptase Didanosine Zidovudine

26 CARRIERS INHIBITORS FALSE SUBSTRATES Choline carrier (nerve terminal) Hemicholine Noradrenaline uptake 1 Tricyclic antidepressants Cocaine NE uptake (vesicular) Reserpine Na+/K+/Cl- co-transporter (loop of Henle) Furosemide Na+/K+ pump Cardiac glycoside Proton pump (stomach) Omeprazole

27 RECEPTOR FAMILIES Intracellular receptors: the ligand must get into the cells. e.g. ( nitric oxide (NO), corticosteroids, mineralocorticoids, sex steroids, vitamin D and thyroid hormone). The observed response needs 30 minutes or more. Ligand-Regulated Transmembrane Enzymes Including Receptor Tyrosine Kinases (insulin, epidermal growth factor EGF, platelet-derived growth factor PDGF, atrial natriuretic factor ANF, transforming growth factor-β TGF β, other trophic hormones). Ligand-Gated ion chanels. The response very fast (few ms) e.g. Nicotinic, GABA receptors G Protein-coupled receptors (response second to mins)

28 Known transmembrane signaling mechanisms:
1: A lipid-soluble chemical signal crosses the plasma membrane and acts on an intracellular receptor (which may be an enzyme or a regulator of gene transcription); 2: the signal binds to the extracellular domain of a transmembrane protein, thereby activating an enzymatic activity of its cytoplasmic domain; 3: the signal binds to the extracellular domain of a transmembrane receptor bound to a protein tyrosine kinase, which it activates; 4: the signal binds to and directly regulates the opening of an ion channel; 5: the signal binds to a cell-surface receptor linked to an effector enzyme by a G protein. (R, receptor; G, G protein; E, effector [enzyme or ion channel].) (2001 The McGraw Hill Companies)

29 Mechanism of glucocorticoid action.
The glucocorticoid receptor polypeptide is schematically depicted as a protein with three distinct domains. A heat-shock protein, hsp90, binds to the receptor in the absence of hormone and prevents folding into the active conformation of the receptor. Binding of a hormone ligand causes dissociation of the hsp90 stabilizer and permits conversion to the active configuration.

30 Mechanism of activation of the EGF receptor, a representative receptor tyrosine kinase. The receptor polypeptide has extracellular and cytoplasmic domains, depicted above and below the plasma membrane. Upon binding of EGF (circle), the receptor converts from its inactive monomeric state (left) to an active dimeric state (right), in which two receptor polypeptides bind noncovalently in the plane of the membrane. The cytoplasmic domains become phosphorylated (P) on specific tyrosine residues (Y) and their enzymatic activities are activated, catalyzing phosphorylation of substrate proteins (S). / The McGraw Hill Companies, Inc./

31 Cytokine receptors, like receptor tyrosine kinases, have extracellular and intracellular domains and form dimers. However, after activation by an appropriate ligand, separate mobile protein tyrosine kinase molecules (JAK) are activated, resulting in phosphorylation of STAT molecules. STAT dimers then travel to the nucleus, where they regulate transcription. (2001 The McGraw Hill Companies)

32 (2001 The McGraw Hill Companies, Inc. )
The nicotinic acetylcholine receptor, a ligand-gated ion channel. The receptor molecule is depicted as embedded in a rectangular piece of plasma membrane, with extracellular fluid above and cytoplasm below. Composed of five subunits (two a, one b, one g, and one d), the receptor opens a central transmembrane ion channel when acetylcholine (ACh) binds to sites on the extracellular domain of its a subunits. (2001 The McGraw Hill Companies, Inc. )

33 G-PROTEIN-COUPLED RECEPTORS
Consist of extracellular N-terminal and intracellular C-terminal domain connected by a single peptide chain passing the plasma membran seven times and thus forms the extra and intracellular loops. The third intracellular loop is the region to which G-proteins are coupling. G-proteins consists of three subunits , β and . GTP and GDP bind to -subunit. At rest GDP is binding to  (GDP-β, trimer). Upon attachment of agonist to receptor  catayses the conversion of GDP to GTP ( then -GTP complex dissociates from β-complex and interacts with a target protein, eg enzyme Adenylate cyclase). The GTPase activity of the -subunit is enhanced when -GTP complex binds to the target protein and thus results in hydrolysis of GTP to GDP. -GTP and β complexes are the active forms of G-proteins. Main classes of G-protein: Gs, Gi, Gq Cholera toxin acts only on Gs→ persistent activation Pertussis toxin acts on Gi Targets For G-proteins: second messengers (adenylate cyclase switch on by Gs (cAMP production) ; Phospholipase C (generates IP3 and DAG) ; Ion channels (Ca2+, K+). e.g. adrenaline, acetylcholine, dopamine, serotonin, opioids.

34 PIP2 IP3 DAG phospholipase C Activation of protein kinase C
Release of intracellular Ca2+ PIP2= Phosphatidylinositol biphosphate

35 The guanine nucleotide-dependent activation-inactivation cycle of G proteins. The agonist activates the receptor (R), which promotes release of GDP from the G protein (G), allowing entry of GTP into the nucleotide binding site. In its GTP-bound state (G-GTP), the G protein regulates activity of an effector enzyme or ion channel (E). The signal is terminated by hydrolysis of GTP, followed by return of the system to the basal unstimulated state. Open arrows denote regulatory effects. (Pi, inorganic phosphate.) /2001 The McGraw Hill Companies/

36 Transmembrane topology of a typical serpentine receptor
Transmembrane topology of a typical serpentine receptor. The receptor's amino (N) terminal is extracellular (above the plane of the membrane), and its carboxyl (C) terminal intracellular. The terminals are connected by a polypeptide chain that traverses the plane of the membrane seven times. The hydrophobic transmembrane segments (light color) are designated by roman numerals (I-VII). The agonist (Ag) approaches the receptor from the extracellular fluid and binds to a site surrounded by the transmembrane regions of the receptor protein. G proteins (G) interact with cytoplasmic regions of the receptor, especially with portions of the third cytoplasmic loop between transmembrane regions V and VI. The receptor's cytoplasmic terminal tail contains numerous serine and threonine residues whose hydroxyl (-OH) groups can be phosphorylated. This phosphorylation may be associated with diminished receptor-G protein interaction. (2001 The McGraw Hill Companies, Inc. )

37 Possible mechanism for desensitization of the b-adrenoceptor
Possible mechanism for desensitization of the b-adrenoceptor. The upper part of the figure depicts the response to a b-adrenoceptor agonist (ordinate) versus time (abscissa). The break in the time axis indicates passage of time in the absence of agonist. Temporal duration of exposure to agonist is indicated by the light- colored bar. The lower part of the figure schematically depicts agonist-induced phosphorylation (P) by b-adrenoceptor kinase (b-adrenergic receptor kinase, bARK) of carboxyl terminal hydroxyl groups (-OH) of the b-adrenoceptor. This phosphorylation induces binding of a protein, b-arrestin (b-arr), which prevents the receptor from interacting with Gs. Removal of agonist for a short period of time allows dissociation of b-arr, removal of phosphate (Pi) from the receptor by phosphatases (P'ase), and restoration of the receptor's normal responsiveness to agonist The McGraw Hill Companies

38 The cAMP second messenger pathway.
Key proteins include hormone receptors (Rec), a stimulatory G protein (Gs), catalytic adenylyl cyclase (AC), phosphodiesterases (PDE) that hydrolyze cAMP, cAMP- dependent kinases, with regulatory (R) and catalytic (C) subunits, protein substrates (S) of the kinases, and phosphatases (P'ase), which remove phosphates from substrate proteins. Open arrows denote regulatory effects. The McGraw Hill Companies, Inc

39 The Ca2+- phosphoinositide signaling pathway.
Key proteins include hormone receptors (R), a G protein (G), a phosphoinositide-specific phospholipase C (PLC), protein kinase C (PK-C), substrates of the kinase (S), calmodulin (CaM), and calmodulin-binding enzymes (E), including kinases, phosphodiesterases, etc. (PIP2, phosphatidylinositol- 4,5-bisphosphate; DAG, diacylglycerol. Asterisk denotes activated state. Open arrows denote regulatory effects.) 2001 The McGraw Hill Companies, Inc.

40 Possible relations between the therapeutic and toxic effects of a drug, based on different receptor-effector mechanisms.

41 The relationship between dose and effect can be separated into pharmacokinetic (dose-concentration) and pharmacodynamic (concentration-effect) components. Concentration provides the link between pharmacokinetics and pharmacodynamics and is the focus of the target concentration approach to rational dosing. The three primary processes of pharmacokinetics are absorption, distribution, and elimination.