Annabell C. Segarra, Associate Professor

Phone: (787) 758-2525 ext. 1965



University of Puerto Rico




University of Puerto Rico




New York University




New York University




The Rockefeller University




Research Interests

The research in our laboratory focuses on the neurochemical substrates that participate in mediating sex differences in motivated behavior.  For the last 18 years, my laboratory has studied the mechanisms by which sex steroids modulate the response to drugs of abuse, such as cocaine and opioids. Our studies use a whole system approach, measuring behavioral changes in response to the drug, and investigating the signal transduction mechanisms involved.  Where we lack the equipment and/or expertise, we have established collaborations with scientists on the island and abroad.  This was the case of our fMRI studies, done in collaboration with Drs Ferris and Febo of Northeastern University, and our collaborative microdialysis studies with Dr. Toni Shippenberg at NIDA. In addition, I established a core facility for image analysis 20 years ago, enlarged it to include confocal microscopy, and continue to direct and secure funds for this facility.

Presently at UPR, MSC

Professor, Dept of Physiology,
Coordinator – Graduate Program in Physiology
Academic Senator for Medicine
Chair, Institutional Radiation Safety Committee

Past students


Wilfredo López-Ojeda, PhD (1996) –  Asst Professor-Univ of South Florida, Orlando, FL 
Jocelyn Montalvo, MD (MS-1997) – Pediatrician-Dept of Pediatrics, UPR, Medical Sciences

Doctor of Philosophy

Marcelo Febo, PhD (2002)- Asst Professor-Univ of Florida, Dept of Psychiatry, Gainesville, FL
Carlos Mejías-Aponte, PhD (2003) – Postdoc-National Institutes of Drug Abuse, Baltimore, MD
Natasha Lugo-Escobar, PhD (2010)- Postdoc- National Institutes of Drug Abuse, Baltimore, MD
Anabel Puig-Ramos, PhD (2010)- Research Scientist, Dept of Pediatrics, UPR, Medical Sciences
Raissa Menéndez-Delmestre, PhD (2011)- Postdoc-Dept of Neurology, UPR, Medical Sciences


  • Segarra, AC, Torres-Díaz,YM, Silva, RD, Puig-Ramos, A, Menéndez-Delmestre, R, Rivera-Bermúdez, JG, Amadeo, W and JL Agosto. Estradiol enhances the behavioral effects of cocaine by facilitating contextual cues via estrogen receptors.  Submitted to Hormones and Behavior.

  • Menéndez-Delmestre R, Segarra AC. 2011, Testosterone is essential for cocaine sensitization in male rats. Physiol Behav 102(1):96-104.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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 Segarra2003. Estrogen dependent alterations in D2/D3 induced G protein activation in cocaine-sensitized female rats. J Neurochem. 86 405-412.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.

  • 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.