Expression of kinin B1 and B2 receptors in mice abdominal aorta: a comparative study on normal and transgenic animals

• Grant number: 06/01995-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2006
• End date: December 31, 2006
• Field of knowledge: Biological Sciences - Pharmacology - Biochemical and Molecular Pharmacology
• Principal Investigator: Suma Imura Shimuta
• Grantee: Eliete da Silva Rodrigues
• Host Institution: Departamento de Biofísica. Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil

Abstract

Kinins are proinflammatory peptides that act as local hormones and activate the release of endothelium-derived relaxing factor and prostaglandins, increase vascular permeability, contract or relax smooth muscle and provoke pain. Most of these effects are mediated by the B2 receptor, which belongs to a family of peptide hormone receptors linked to G proteins (for a review, see Leeb-Lundberg et al., 2005). Another type of kinin receptor, the B1 receptor is generally silent, absent or expressed at very low levels, in healthy tissues, but is induced in response to pathological insults during which it mediates cardiovascular and nociceptive responses (Marceau et al., 1998). Indeed, Pesquero et al. (2000) has shown that in mice lacking the B1 receptor gene, endotoxin-induced hypotension and accumulation of polimorphonuclear leukocytes in inflamed tissue were dramatically attenuated. Mouse has been considered a suitable strain in the generation of genetically altered animal and used to find out whether the elimination of one receptor may interfere with the expression and function of other receptor system. Concerning kinin B1 and B2 receptors in the mouse, systematic studies have been performed in nonvascular tissues as stomach and urinary bladder (Nsa Allogho et al., 1995) and trachea (Li et al., 1998) isolated from the mice. They found that the stomach and the trachea coexpress B1 and B2 receptors whereas the urinary bladder possesses only B1 receptor. However a study on mouse vascular reactivity to contractile and relaxant responses to kinins has not been performed yet. The aim of this study is to characterize the abdominal aorta from the C57BL/6 mouse towards the expression of kinin B1 and B2 receptors. Since mice with genetic deletion of kinin B1 or B2 receptors are available in our laboratoy, we will compare the expression of both kinin receptors in normal and in B1 or B2 receptor knockout mice, using the Real Time PCR technique. This study will lead us to to find out whether the elimination of B1 or B2 receptors interferes with the expression of the other receptor system. The result will be expressed as expression of B1 or B2 receptor mRNA levels in aorta from normal and transgenic mice, using the β-actin mRNA levels as reference.