Essays on Signal Transduction

Blood Pressure, Hypertension and the Nervous System

Cardiovascular activities within the human body are generally facilitated by the regulation of the sympathetic and parasympathetic afferent and efferent nerve fibers. Blood pressure is the relationship between the vascular resistance and the amount of blood that the heart pumps per minute (i.e. cardiac output). Cardiac output is affected by the following factors: end-diastolic volume, cardiac muscle contraction, and heart rate. While the sympathetic nervous system controls the blood volume and the tone of venous smooth muscle (determinants of end-diastolic volume) alone, the myocardial contraction and heart rate is controlled by both sympathetic and parasympathetic regions of the autonomic ...

1. Introduction Opioids such as codeine and morphine, are the active pharmaceutical ingredients of many drugs such as pain relievers (analgesics), cough suppressants, sedatives, etc. Opioids are derivatives of opium and bind to the μ-opioid receptor (μOR). The coupling of the μOR to Gi, the inhibitory subunit of the G-protein, blocks the activation of adenylyl cyclase and results in the analgesic effect. The opioid receptors belong to the G protein-coupled receptors (GPCRs) superfamily and specifically to the rhodopsin-like family A. These receptors consist of two closely related members, namely, δOR and κOR (Manglik et al. 2012, p. 322). ...

Cancer is the abnormal proliferation and differentiation of cells in an abnormal tissue incongruent with the growth pattern of normal cells that persists even after the stimuli that evoked the change is withdrawn. The cell cycle check points at G1, G2 and at the end of metaphase that prevent transmission of genetically damaged DNA fail to occur. Transmission of faulty DNA results in either an abnormal rate of cell division and multiplication or abnormally constituted daughter cells. The genes affected are the normal regulatory genes including growth promoting proto-oncogenes-normal genes that are prone to becoming cancerous on mutation ...

Introduction

The Extracellular signal-regulated kinases (ERK) pathway is one of the most important signal transduction systems in a cell. This pathway regulates a lot of the fundamental processes of the cell including cell growth control and also cell death. The ERK pathway’s basic structure includes a couple of phosphorylations. The pathway provides a channel for the passing of signals from receptor that is located on the cell surface to the DNA inside the cell nucleus. The signal transduction process through the ERK pathway is a complex process. Initially, the signaling molecule, that is, the epidermal growth factor (EGF) usually binds itself to a receptor ...

Prions are infectious proteins that are usually linked with the occurrence of neurodegenerative disorders in humans as well as many other mammals. They belong to the class of misfolded proteins and are the causative agents for the different transmissible diseases, mainly encephalopathy that can be defined by the changes in the anatomy accompanied by Pathophysiological origin that follow Mendelian genetics. The main characterization of the disease is the aggregation of proteins in the neurological system leading to degenerative brain diseases that are fatal and are incurable at present. Murray et al. (2004, p.37) have stressed that the transmissible ...