DepartmentCellular and Integrative Physiology
Raphael Perim, Ph.D.
Lab Affiliation: Glenn M. Toney, Ph.D. I am a research instructor in Dr. Toney laboratory at the University of Texas Health Science Center at San Antonio. As an integrative physiologist, I am fascinated by synaptic mechanisms giving rise to plastic changes in cardiovascular and respiratory neuronal network responding to physiological challenges such as acute intermittent hypoxia. Potential therapeutic implications are expected out of this pioneering work as acute episodes of intermittent hypoxia has the capacity to restore beyond spontaneous recovery respiratory and non-respiratory motor function; and yet very little is known about the impact of better cardiovascular regulation on treating conditions leading to hypotension, orthostatic intolerance, and blood flow limitation to the central nervous system such as spinal cord injury.
Recently, I developed a mice preparation to study acute intermittent hypoxia-induced sympathetic long-term facilitation. Sympathetic long-term facilitation is a form of plasticity characterized by a progressive increase in sympathetic nerve activity that last for hours. To study this phenomenon, post-ganglionic renal sympathetic nerve activity is recorded while blood pressure and ventilation are maintained within physiological levels. This mice preparation opens a new realm of possibilities, taking advantage of cutting-edge techniques to design neurophysiological experiments that will greatly improve our understanding of synaptic mechanisms to sympathetic long-term facilitation.
My recent findings revealed robust acute intermittent hypoxia-induced renal sympathetic long-term facilitation in mice for the first time, expanding previous work. I am currently exploring the likely involvement of hypothalamic paraventricular nucleus in driving sympathetic nerve activity and applying optogenetic techniques in vivo and in vitro to selectively stimulate/inhibit specific regions of interested and unravel relevant players.
University of Sao Paulo, School of Medicine of Ribeirao Preto, Department of physiology, Brazil
Neurophysiological experiments Data analysis Statistical analysis
Awards & Accomplishments
Invited Oral Presentation, Control of Breathing Mixer – Experimental Biology (2017) Research Recognition Award, American Physiological Society – Respiratory Section (2017) Invited Oral Presentation, Control of Breathing Mixer – Experimental Biology (2016) McKnight Brain Institute Travel Award, University of Florida (2016) Poster award, University of Florida – Neuroscience Retreat (2016) Poster award, Sao Paulo State University – Bioscience Institute (2013)
Perim RR, Sunshine MD, Welch JF, Santiago J, Holland A, Ross A, Mitchell GS, Gonzalez-Rothi EJ. Daily acute intermittent hypoxia enhances phrenic motor output and stimulus-evoked phrenic responses in rats. J Neurophysiol. 2021 Sep 1;126(3):777-790. doi: 10.1152/jn.00112.2021. Epub 2021 Jul 14. PMID: 34260289 Perim RR, Gonzalez-Rothi EJ, Mitchell GS. Cervical spinal injury compromises caudal spinal tissue oxygenation and undermines acute intermittent hypoxia-induced phrenic long-term facilitation. Exp Neurol. 2021 Aug;342:113726. doi: 10.1016/j.expneurol.2021.113726. Epub 2021 Apr 26. PMID: 33915165 Perim RR, El-Chami M, Gonzalez-Rothi EJ, Mitchell GS. Baseline Arterial CO2 Pressure Regulates Acute Intermittent Hypoxia-Induced Phrenic Long-Term Facilitation in Rats. Front Physiol. 2021 Feb 24;12:573385. doi: 10.3389/fphys.2021.573385. eCollection 2021. PMID: 33716760 Free PMC article. Welch JF, Perim RR, Argento PJ, Sutor TW, Vose AK, Nair J, Mitchell GS, Fox EJ. Effect of acute intermittent hypoxia on cortico-diaphragmatic conduction in healthy humans. Exp Neurol. 2021 May;339:113651. doi: 10.1016/j.expneurol.2021.113651. Epub 2021 Feb 16. PMID: 33607080 Tadjalli A, Seven YB, Perim RR, Mitchell GS. Systemic inflammation suppresses spinal respiratory motor plasticity via mechanisms that require serine/threonine protein phosphatase activity. J Neuroinflammation. 2021 Jan 19;18(1):28. doi: 10.1186/s12974-021-02074-6. PMID: 33468163 Free PMC article. Perim RR, Kubilis PS, Seven YB, Mitchell GS. Hypoxia-induced hypotension elicits adenosine-dependent phrenic long-term facilitation after carotid denervation. Exp Neurol. 2020 Nov;333:113429. doi: 10.1016/j.expneurol.2020.113429. Epub 2020 Jul 29. PMID: 32735873 Free PMC article. Welch JF, Sutor TW, Vose AK, Perim RR, Fox EJ, Mitchell GS. Synergy between Acute Intermittent Hypoxia and Task-Specific Training. Exerc Sport Sci Rev. 2020 Jul;48(3):125-132. doi: 10.1249/JES.0000000000000222. PMID: 32412926 Free PMC article. Review. Perim RR, Fields DP, Mitchell GS. Spinal AMP kinase activity differentially regulates phrenic motor plasticity. J Appl Physiol (1985). 2020 Mar 1;128(3):523-533. doi: 10.1152/japplphysiol.00546.2019. Epub 2020 Jan 23. PMID: 31971473 Free PMC article. Perim RR, Mitchell GS. Circulatory control of phrenic motor plasticity. Respir Physiol Neurobiol. 2019 Jul;265:19-23. doi: 10.1016/j.resp.2019.01.004. Epub 2019 Jan 11. PMID: 30639504 Free PMC article. Review. Perim RR, Fields DP, Mitchell GS. Protein kinase Cδ constrains the S-pathway to phrenic motor facilitation elicited by spinal 5-HT7 receptors or severe acute intermittent hypoxia. J Physiol. 2019 Jan;597(2):481-498. doi: 10.1113/JP276731. Epub 2018 Dec 2. PMID: 30382587 Free PMC article. Seven YB, Perim RR, Hobson OR, Simon AK, Tadjalli A, Mitchell GS. Phrenic motor neuron adenosine 2A receptors elicit phrenic motor facilitation. J Physiol. 2018 Apr 15;596(8):1501-1512. doi: 10.1113/JP275462. Epub 2018 Mar 11. PMID: 29388230 Free PMC article. Perim RR, Fields DP, Mitchell GS. Cross-talk inhibition between 5-HT2B and 5-HT7 receptors in phrenic motor facilitation via NADPH oxidase and PKA. Am J Physiol Regul Integr Comp Physiol. 2018 May 1;314(5):R709-R715. doi: 10.1152/ajpregu.00393.2017. Epub 2018 Jan 31. PMID: 29384698 Free PMC article. Perim RR, Amorim MR, Bonagamba TLLGH, Machado BH. Previous exposure to chronic intermittent hypoxia blunts the development of one-kidney, one-clip hypertension in rats. Exp Physiol. 2018 Apr 1;103(4):473-482. doi: 10.1113/EP086734. Epub 2018 Feb 14. PMID: 29359403 Perim RR, Bonagamba LG, Machado BH. Cardiovascular and respiratory outcome of preconditioned rats submitted to chronic intermittent hypoxia. Exp Physiol. 2015 Sep;100(9):1008-17. doi: 10.1113/EP085237. PMID: 26195236 Signorelli GR, Perim RR, Santos TM, Araujo CG. A pre-season comparison of aerobic fitness and flexibility of younger and older professional soccer players. Int J Sports Med. 2012 Nov;33(11):867-72. doi: 10.1055/s-0032-1311597. Epub 2012 Jun 15. PMID: 22706948 Perim RR, Signorelli GR, Araújo CG. Stability of relative oxygen pulse curve during repeated maximal cardiopulmonary testing in professional soccer players. Braz J Med Biol Res. 2011 Jul;44(7):700-6. doi: 10.1590/s0100-879×2011007500073. Epub 2011 Jun 1. PMID: 21837356 Perim RR, Signorelli GR, Myers J, Arena R, de Araújo CG. The slope of the oxygen pulse curve does not depend on the maximal heart rate in elite soccer players. Clinics (Sao Paulo). 2011;66(5):829-35. doi: 10.1590/s1807-59322011000500020. PMID: 21789388 Free PMC article.