Heme oxygenase: protective enzyme or portal hypertensive molecule?

Slides:

Advertisements

Similar presentations

G Linked Receptors (Continued…….). Serine/Threonine Protein Phosphatases Rapidly Reverse the Effects of A-Kinase.

Advertisements

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings Twitch time course Duration of twitch is largely governed by rate of sequestration.

Muscles and Muscle Tissue: Smooth Muscle Part C2 Prepared by Janice Meeking, W. Rose, and Jarvis Smith. Figures from Marieb & Hoehn 8 th ed. Portions copyright.

Smooth Muscle Excitation - Contraction

Medical Biochemistry Membranes: Membrane receptors; G-proteins Lecture 73 Membranes: Membrane receptors; G-proteins Lecture 73.

WINDSOR UNIVERSITY SCHOOL OF MEDICINE

Cell Communication II Chapter 15. An animal cell depends on extracellular signals to survive or divide.

Channel-linked Receptors aka: ligand-gated channels a receptor type seen in synaptic transmission rapid response (ms) limited response –depolarization.

Subtypes of Alpha Adrenergic Receptors

Second Messengers and Signal Transduction

CGMP Intracellular Signal cGMP is made from GTP by the enzyme gaunylyl cyclase. Atrial natriuretic peptide and nitric oxide function through this Signal.

Smooth Muscle  Spindle-shaped cells 2-10  m across & ~100  m long  Have a thin endomysium  Organized into longitudinal and circular layers  Found.

Chap. 15 Problem 2 Signaling systems are classified based on the distance over which they act. Endocrine signaling acts over long distances within the.

Smooth Muscle Unstriated muscle associated with visera. (Compare to skeletal muscle) Controlled by autonomic nervous system, hormones and paracrines. actin/myosin.

Part V Second Messengers. The first messengers being the extracellular signal molecules and the third messengers being the large protein kinases and phosphatases.

Bundle of fibers Muscle fiber (muscle cell) Myofibril Sarcomere.

1 Receptor terminology Protein-ligand properties: specificity, saturation, affinity, competition Antagonist: binds to receptor site and inhibits Agonist:

Visceral Muscle. How is the gut organized anatomically?

Cell Signaling. Local Signaling Paracrine Paracrine Synaptic Synaptic.

 Signaling molecules that function within an organism to control metabolic processes within cells, the growth and differentiation of tissues, the synthesis.

Chapter 14. Signal Transduction Signal transduction is the process by which an extracellular signal alters intracellular events. 1. First and second messengers.

Cell Signaling (BIO-203) Lecture 3. Types of G proteins Humans have 21 different G α subunits ( kDa) 6 G β subunits (35-35 kDa) 12 G γ subunits.

11.3 Transduction: Cascades of molecular interactions relay signals from receptors to target molecules in the cell  Signal transduction usually involves.

CHAPTER 11 CELL COMMUNICATION Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Section C: Signal-Transduction Pathways 1.Pathways.

Contraction Mechanism Actin and myosin interact via to the sliding filament mechanism Resting State –Actin bound by caldesmon –Myosin light chain (MLC)

Comparison of Properties of: Skeletal, Smooth & Cardiac Muscle Comparison of functional organisation, electrical properties and mechanical properties of.

TARGETS FOR G-PROTEINS The main targets for G-proteins, through which GPCRs control different aspects of cell function are: adenylyl cyclase, the enzyme.

Revised curriculum (1) December 16 (Tuesday) Second messengers

A simplified diagram of smooth muscle contraction and the site of action of calcium channel-blocking drugs. Contraction is triggered (red arrows) by influx.

Hormones and Signal Transduction

OVERVIEW: Signals for cell surface receptors (hydrophilic):

Cell Communication Part II

What does the following have in common?

Volume 4, Issue 3, Pages (June 2006)

Cell Communication (Signaling) Part 2

Smooth Muscle cells contain actin and myosin, but are quite different from skeletal and cardiac myocytes. 1) Where do we find smooth muscle under involuntary.

Signal trasduction via cAMP

Patrick Delmas, Bertrand Coste, Nikita Gamper, Mark S. Shapiro Neuron

Cell Communication (Signaling) Part 2

Intracellular Receptors

HFpEF, a Disease of the Vasculature: A Closer Look at the Other Half

Primary Immunodeficiencies

Effect of Benidipine in Human Internal Mammary Artery and Clinical Implications Hai-Tao Hou, BE, Jun Wang, BA, Zheng-Qing Wang, MD, Xiao-Cheng Liu, MD,

Daniel A. Langer, Vijay H. Shah Journal of Hepatology

Cell Communication (Signaling) Part 2

Development of PI3K/AKT/mTOR Pathway Inhibitors and Their Application in Personalized Therapy for Non–Small-Cell Lung Cancer Vassiliki Papadimitrakopoulou,

Cellular mechanisms of cyclic nucleotide-induced vasorelaxation

PKB Binding Proteins Cell

Mechanism of Hormonal Action

Regulation of Metabolism

Mark S Taylor, A.Marie McMahon, Jason D Gardner, Joseph N Benoit

Calcium Signals Tune the Fidelity of Transcriptional Responses

Chapter 14 Blood Pressure – Regulation and Pathology

Live Longer sans the AT1A Receptor

Guo-Wei He, MD, DSc, David P. Taggart, FRCS

Intracellular Ca2+ Release and Ischemic Axon Injury

Hypertension, Na+/Ca2+ exchanger, and Na+, K+-ATPase

Superiority of hyperpolarizing to depolarizing cardioplegia in protection of coronary endothelial function Guo-Wei He, MD, PhD, Cheng-Qin Yang, MD The.

Cell Communication (Signaling) Part 2

Chapter 16 Cell Communication.

Dr Brian J. Harvey, Maria Higgins Kidney International

Eric N. Johnson, PhD, Kirk M. Druey, MD

Neuronal Calcium Signaling

Hypoxic pulmonary vasoconstriction in cardiothoracic surgery: basic mechanisms to potential therapies Ben M Tsai, MD, Meijing Wang, MD, Mark W Turrentine,

The complex field of interplay between vasoactive agents

Targeting TNF-α: A novel therapeutic approach for asthma

Editorial II British Journal of Anaesthesia

Reversible Binding of Phosphate

Volume 87, Issue 3, Pages (September 2004)

Spasm in Arterial Grafts in Coronary Artery Bypass Grafting Surgery

Presentation transcript:

Heme oxygenase: protective enzyme or portal hypertensive molecule? Richard Moreau Journal of Hepatology Volume 34, Issue 6, Pages 936-939 (June 2001) DOI: 10.1016/S0168-8278(01)00090-3

Fig. 1 Regulation of normal arterial smooth muscle cell (SMC) tone by the 20-kDa light chain of myosin (MLC20). In SMC, the increase and decrease in cytosolic free Ca2+ are the main mechanisms that induce contraction and relaxation, respectively. Increased Ca2+ binds to calmodulin, and the association of the Ca2+-calmodulin complex with the catalytic subunit of myosin light-chain kinase activates this enzyme to phosphorylate serine 19 of MLC20. Phosphorylation of serine 19 of MLC20 allows the myosin ATPase to be activated by actin and SMC to contract. A decrease in cytosolic free Ca2+, via a reduction in the Ca2+-calmodulin complex, inactivates myosin light-chain kinase and permits dephosphorylation of MLC20 by myosin light-chain phosphatase. These mechanisms result in deactivation of myosin ATPase and relaxation. Dephosphorylation of MLC20 causes desensitization of the contractile apparatus to Ca2+. Journal of Hepatology 2001 34, 936-939DOI: (10.1016/S0168-8278(01)00090-3)

Fig. 2 Molecular mechanisms for cyclic GMP-induced relaxation in normal arterial smooth muscle cells. Cyclic GMP (probably via the activation of PKGIα) induces relaxation by decreasing [Ca2+]i and desensitizing the contractile apparatus to Ca2+. Cyclic GMP decreases [Ca2+]i by inhibiting L-type Ca2+-channels (and reducing the entry of extracellular Ca2+). cGMP-induced L-type Ca2+-channel inhibition may be direct or indirect (via SMC membrane hyperpolarization). Membrane hyperpolarization may result from activation of large-conductance, Ca2+-activated K+ (BKCa) channels or of the Na+-K+ ATPase. Cyclic GMP also decreases [Ca2+]i by inducing Ca2+ extrusion and sequestration (via stimulation of Ca2+-ATPases located in the plasma membrane and the membrane of the sarcoplasmic reticulum, respectively). Cyclic GMP decreases [Ca2+]i by reducing the mobilization of intracellular Ca2+ (by inhibiting the production of inositol trisphosphate (InsP3) due to the activation of the heterotrimeric G protein (G)/phospholipase C (PLC) signalling pathway). Finally, cyclic GMP may also decrease InsP3–induced mobilization of intracellular Ca2+ by inhibiting the InsP3 receptor which is in the membrane of the sarcoplasmic reticulum. On the other hand, cyclic GMP desensitizes the contractile apparatus to Ca2+ by activating myosin light-chain phosphatase, resulting in MLC20 dephosphorylation (see Fig. 1, caption). The plus sign means activation by cyclic GMP; the minus sign means inhibition by cyclic GMP. Journal of Hepatology 2001 34, 936-939DOI: (10.1016/S0168-8278(01)00090-3)