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THE ROLE OF VENTROMEDIAL PREFRONTAL CORTEX ON EFFECT OF ACUPUNCTURE IN CARDIOVASCULAR RESPONSES INDUCED BY SENSORY STIMULI IN RATS

Grant number: 12/03681-6
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): September 01, 2012
Effective date (End): February 28, 2014
Field of knowledge:Biological Sciences - Pharmacology - General Pharmacology
Principal Investigator:Leonardo Resstel Barbosa Moraes
Grantee:Josie Resende Torres da Silva
Home Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Pain is a complex perceptual experience involving all aspects of life. This response is resulting from central integration of peripheral nerve impulses triggered by local stimuli and signalizes the supra spinal centers about the tissue lesions, allowing defense mechanisms to be adopted. Although the reflex movements are more commonly used to assess pain in animal models, the validity of this approach is still uncertain. As the painful experience of the animal cannot be known, assumptions about the level of pain are made based on inferences. Thus, the physiological measurements could be used as additional data in the interpretation of pain in animals. The ventromedial frontal cortex (vMPFC) is a limbic system structure that is involved in the modulation of autonomic responses by influencing the hormonal systems, cardiovascular and gastrointestinal in rats and structural and physiological changes in neurons of this nucleus are related to the hyperalgesia induced nerve ligation. One method to compare nociception with cardiovascular reflex changes is by behavioral pain tests because nociception modulates the heart rate and blood pressure, suggesting your use as indicators of pain in animals. Knowing that the technique of acupuncture treatment can reduce pain in animal models, your use in the study of changes of cardiovascular reflex induced by nociception has been not demonstrated. Despite the use of acupuncture as a support in a series of heart disease, little is known about the mechanisms that underlie their actions. Clinical and experimental studies suggest that acupuncture maybe beneficial in cardiovascular diseases such as hypertension, arrhythmias, angina pectoris and myocardial infarction. However, no studies comparing the effects of different modes of acupuncture stimulation on cardiovascular reflex responses after induction of painful stimuli. Thus, the present study aims to evaluate the participation of vMPFC cardiovascular changes induced hyperalgesia by nerve ligation and the participation in different types of acupuncture protocols. The following assumptions will be tested: a) the vMPFC is an important modulator of cardiovascular reflex responses induced by various types of pain in rats, 2) EA is more effective that MA in modulation of cardiovascular reflex responses induced by different models of pain in rats, 3) there is an increased inhibition of pressure reflexes with EA using stimulation of low or high-frequency in acupuncture points overlying deep somatic nerves, or the two sets of simultaneous stimulation of acupuncture points, 4) inhibition of pressure reflexes by acupuncture involve NMDA receptors, TRPV1, CB1 or the NOS in vCPFM.