Dr. Annabell C. Segarra

Department Chair
Dr. Annabell C. Segarra


B.S. 1974BiologyUniversity of Puerto Rico, Rio Piedras, PR
M.S. 1977Biology (Endocrinology)University of Puerto Rico, Rio Piedras, PR
Ph.D. 1988NeurophysiologyNew York University, Wash Sq, NY, NY
Postdoc 1989-91NeuroendocrinologyThe Rockefeller University, NY, NY


I am a Professor and Chair of the Physiology Department at the School of Medicine of the University of Puerto Rico Medical Sciences Campus.  Research in our laboratory is investigating how sex steroids and rearing conditions modulate adolescent susceptibility to drugs of abuse. Our long-term goal is to elucidate the mechanisms by which alterations in brain neurochemistry and/or synaptic connectivity result in dysfunctional motivational and reward circuitry.

I am also committed to increase diversity in STEM disciplines, by serving as a mentor to graduate and undergraduate students from diverse backgrounds.  I serve as mentor to undergraduate and graduate students within the UPR system and via professional societies such as Society for Neuroscience, American Physiological Society (APS), SACNAS and World Women in Neuroscience. Mentoring includes one-on-one development of research skills (discussion of research data, how to give a scientific talk, prepare a poster, presentation skills, manuscript writing, networking), providing talks on these subjects as well as providing emotional support when needed.  In addition, I volunteer as an evaluator of the NSF graduate fellowship program (GRFP) and the Porter Fellowship committee of the APS.


The research in Dr. Segarra’s laboratory focuses on the interactions between sex steroids and glucocorticoids in modulating motivation, such as addictive behavior. The long-term goal of the laboratory is to elucidate the mechanisms by which alterations in brain neurochemistry and/or synaptic connectivity result in dysfunctional motivational and reward circuitry. Since many of these motivated behaviors are sexually dimorphic, the experiments focus on the developmental window when this dimorphism is established, and the factors involved. Current research efforts are concentrated in studying the interactions between sex steroids, housing conditions, and exercise in modulating the behavioral response to cocaine. Researchers in her lab have found that rearing young rats in isolation increases anxiety and their behavioral response to drugs of abuse.  We are currently exploring if exercise can mitigate these effects. By studying the interaction between limbic brain neurochemistry and sex steroids in normal and aberrant motivated behaviors, the laboratory can obtain physiologically relevant information that may contribute to elucidate the mechanisms involved in many psychiatric disorders and identify gender bias. A better understanding of the factors that lead to differential sensitivity to drugs of abuse is crucial for the development of pharmacotherapy that is equally effective in males and females.



Wilfredo López-Ojeda (1996) (PhD in 2002); Associate Prof, Wake Forest Sch of Med, NC

Jocelyn Montalvo (1997) (MD in 2001); Associate Prof, Pediatrics, UPR, MSC, PR

Doctor of Philosophy

Marcelo Febo, PhD (2002), Associate Prof, Psychiatry, Univ Florida College of Medicine

Carlos Mejías-Aponte, PhD (2002), Manager, NIDA Histology Core, MD

Natasha Lugo-Escobar, PhD (2010), Director HiSTEP 2.0, NIH, MD

Anabel Puig-Ramos, PhD (2010) Research Scientist, Pediatrics, UPR, MSC, PR

Raissa Menéndez-Delmestre, PhD (2011), Chicago, Ill

Enrique Pérez-Cardona, PhD (2020), Director Education Dept, UPR Carolina, PR


Postdoctoral fellows

Joyce Vélez, PhD, Tech Support Scientist, Agilent Technologies, San Diego, CA

José Agosto-Rivera, Associate Professor, Biology, UPR Rio Piedras, PR


Doctor of Philosophy

Jaime Freire-Arvelo (2021-expected)

Carlos Rivero (2022-expected)


Undergraduate students (of more than 150)

Arianna Rodríguez-Rivera – UPR Humacao

Paula Sciaca Meza- UPR, Rio Piedras

Fred Villanueva-Diaz – UPR, Rio Piedras


UPR, MSC, School of Medicine

  • Departmentt of PhysiologyCarlos A Jiménez-Rivera, PhD, Carlos A Torres, PhD
  • Departmentt of Anatomy: Mark Miller, PhD
  • Deptartment of Physical Medicine and RehabilitationWalter Frontera, MD
  • Department of Internal MedicineYohana de Jesús, MD

UPR, MSC, School of Public Health

  • Department of Environmental HealthLida Orta, PhD
  • Department of Biostatistics and EpidemiologyCruz María Nazario, PhD

UPR, RRP, Natural Sciences

  • Department of BiologyTugrul Giray, PhD, José L Agosto, PhD

Pontificia Universidad Católica de Chile: Katia Gysling, PhD


  • Novoa J, Rivero CJ, Pérez-Cardona EU, Freire-Arvelo JA, Zeger J, Yarur HE, Santiago-Marrero, IG, Agosto-Rivera, JL, González-Pérez, JL, Gysling K and AC Segarra. Social isolation of adolescent male rats increases anxiety and K+-induced dopamine release in the nucleus accumbens: Role of CRF-R1. Eur Journal of Neuroscience (2021): 54:4888-4905.
  •  López OV, Gorantla S, Segarra AC, Andino Norat MC, Álvarez M, Skolasky RL, Meléndez LM.  Sigma-1 Receptor Antagonist (BD1047) Decreases Cathepsin B Secretion in HIV-Infected Macrophages Exposed to Cocaine. J Neuroimmune Pharmacol. 2019 Jun;14(2):226-240. doi: 10.1007/s11481-018-9807-4.
  • Zenón F, Jorge I, Cruz A, Suárez E, Segarra AC, Vázquez J, Meléndez LM, Serrano H.  2016. 18O proteomics reveal increased human apolipoprotein CIII in Hispanic HIV-1+ women with HAART that use cocaine.  Proteomics Clin Appl. 2016 Feb;10(2):144-55.
  • Mosquera L, Shepherd L, Torrado AI, Torres-Diaz YM, Miranda JD, Segarra AC  2015. Comparison of Two Methods of Estradiol Replacement: their Physiological and Behavioral Outcomes.  J Vet Sci Technol. Nov 30; 6(6):276.
  • Ferchmin PA, Andino M, Reyes Salaman R, Alves J, Velez-Roman J, Cuadrado B, Carrasco M, Torres-Rivera W, Segarra A, Martins AH, Lee JE, Eterovic VA.  2014. 4R-cembranoid protects against diisopropylfluorophosphate-mediated neurodegeneration. Neurotoxicology. 44:80-90. PMID: 24928201
  • Zenón F, Segarra AC, Gonzalez M, Meléndez LM. 2014. Cocaine potentiates cathepsin B secretion and neuronal apoptosis from HIV-infected macrophages. J Neuroimmune Pharmacol. 9(5):703-15. PMID: 25209871
  • Mosquera L, Colón JM, Santiago JM, Torrado AI, Meléndez M, Segarra AC, Rodríguez-Orengo JF, Miranda JD. 2014. Tamoxifen and estradiol improved locomotor function and increased spared tissue in rats after spinal cord injury: their antioxidant effect and role of estrogen receptor alpha. Brain Res.1561:11-22.PMID: 24637260
  • Segarra AC, Torres-Díaz YM, Silva RD, Puig-Ramos A, Menéndez-Delmestre R, Rivera-Bermúdez JG, Amadeo W, Agosto-Rivera JL. 2014. Estrogen receptors mediate estradiol’s effect on sensitization and CPP to cocaine in female rats: role of contextual cues. Horm Behav. 65(2):77-87. PMID: 24355096
  • Menéndez-Delmestre R, Segarra AC. 2011, Testosterone is essential for cocaine sensitization in male rats. Physiol Behav 102(1):96-104. PMID: 20932851
  • Febo M, Segarra AC, Stolberg TL, Ferris CF. 2011. BOLD signal response to cocaine varies with sexual receptivity in female rats. Neuroreport. 2011 Jan 5;22(1):19-22. PMID: 21048520
  • Segarra,AC, Agosto-Rivera,JL, Febo,M, Lugo-Escobar,N, Menendez-Delmestre,R, Puig-Ramos,A. and YM Torres-Diaz  2010. Estradiol: A key biological substrate mediating the response to cocaine in female rats. In press – Horm Behav 58(1):33-43. PMID: 20026119
  • Puig-Ramos, A, Santiago, GS and AC Segarra  2008.  U-59693, a kappa opioid receptor agonist, blocks cocaine-induced behavioral sensitization in female rats.  Behav. Neurosci. 122(1): 151-160. PMID: 18298258.
  • Cruz-Orengo, L., Figueroa, JD, Velazquez, I. Torrado, A, Ortiz, C, Hernandez, C, Puig, A, Segarra, AC, Whittemore, SR and JD Miranda 2006. Blocking EphA4 upregulation after spinal cord injury results in enhanced chronic pain. Exp. Neurol. 202(2): 421-433. PMID: 16959251
  • Febo, M, AC Segarra G Nair, K Schmidt, TQ Duong and CF Ferris 2005. The Neural Consequences of Repeated Cocaine Exposure Revealed By Functional MRI in Awake Rats. Neuropsychopharmacol. 30(5):936-943. PMID: 15637636
  • Febo, M, CF Ferris, and AC Segarra. 2005. Estrogen influences cocaine-induced blood oxygen level-dependent signal changes in female rats. J Neurosci. 25(5):1132-1136. PMID: 15689549
  • Febo, M, AC Segarra, JR Tenney, MA Brevard, TQ Duong and CF Ferris 2004. Imaging cocaine-induced changes in the mesolimbic dopaminergic system of conscious rats. J. Neurosci. Methods 139(2): 167-176. PMID: 15488229
  • Febo, M. and AC Segarra. 2004. Cocaine alters GABA B-mediated G-protein activation in the ventral tegmental area of female rats: Modulation by estrogen. Synapse 54:30-36. PMID: 15300882
  • Segarra, AC and SJ Lee 2004. Neuroprotective effects of estrogen. In: Principles of Gender-Specific Medicine. Ed: M Legato, Ch. 11, pp 96-103; Elsevier Science, San Diego, CA.
  • Febo, M, LA González-Rodriguez, DE Capó Ramos, NY González-Segarra and AC Segarra 2003. Estrogen dependent alterations in D2/D3 induced G protein activation in cocaine-sensitized female rats. J Neurochem. 86 405-412. PMID: 12871581
  • Mejías, CA, CA Jiménez and AC Segarra 2002. Sex differences in models of temporal lobe epilepsy: Role of testosterone. Brain Res. 944 (1-2):210-218. PMID: 12106683
  • Febo, M. CA Jiménez and AC Segarra 2002. Estrogen and opioids interact to modulate the locomotor response to cocaine. Brain Res. 943(1):151-161. PMID: 12088849
  • Torres,G, V García, E Sánchez, A Segarra, BK Patterson and LM Meléndez-Guerrero 2001. Expression of the HIV-1 Coreceptors CCR5 and CXCR4 on placental macrophages and the effect of IL-10 on their expression. Placenta Vol. 22 Supp A: Trophoblast Res. Vol. 5: S29-S33.
  • Segarra, AC, A Acosta, JL González, JA Angulo and BS McEwen 1998. Sex differences in estrogenic regulation of preproenkephalin mRNA levels in the POA of peripubertal rats. Mol Brain Res, 60(1): 133-139. PMID: 9748541
  • Segarra, AC 1993. Prenatal Drugs: Effects on sexually dimorphic neuroanatomical and behavioral traits. In: Alcohol and the Endocrine System (Ed. S. Zakhari). National Institutes of Health, National Institute on Alcohol Abuse and Alcoholism, Research Monograph – 23, Ch. 10, pp 205-222.
  • Segarra, AC and BS McEwen 1992. Drug Effects on Sexual Differentiation of the Brain: Role of Stress and Hormones in Drug Actions. In: Maternal Substance Abuse and the Developing Nervous System (Eds: I.S. Zagan and T.A. Slotkin); Ch. 13 pp 323-367; Academic Press, Inc, New York.
  • Segarra, AC, VN Luine and FL Strand 1991. Sexual behavior of male rats is differentially affected by timing of perinatal ACTH administration. Physiol. Behav. 50:689-697. PMID: 1663626
  • McEwen, BS, H Coirini, A Danielsson, M Frankfurt, E Gould, S Mendelson, M Schumacher A Segarra and C Wooley 1991. Steroid and thyroid hormones modulate a changing brain. J. Ster. Biochem. Molec. Biol. 40:1-14. PMID: 1958513
  • Segarra, AC and BS McEwen 1991. Estrogen increases spine density in ventromedial hypothalamic neurons of peripubertal rats. Neuroendocrinol. 54:365-372.
  • Strand,FL, AC Segarra, LA Zuccarelli, J Kume and KJ Rose 1990. Neuropeptides as growth regulating factors. In: A Decade of Neuropeptides, Eds: G.F.Koob, C.A.Sandman and F.L.Strand NYAS, 579 pp.68-90. PMID: 2159746
  • Strand,FL, KJ Rose, JA King, AC Segarra and LA Zuccarelli 1989. ACTH modulation of nerve development and regeneration. Prog. Neurobiol.33:45-85.
  • Strand,FL, AC Segarra, LA Zuccarelli, J Kume and KJ Rose 1989. Neuropeptides: Fail-safe, redundant or special? In: Neuroendocrinology: New Frontiers. Eds.: D.Gupta, H.A.Wollman and M.B.Ranke. Brain Research Promotion, London.
  • Segarra, AC and FL Strand 1989. Perinatal administration of nicotine alters subsequent sexual behavior and testosterone levels of male rats. Brain Res. 480:151-159. PMID: 2713649


Department of Physiology
Phone:(787)758-2525 x1613