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Neuroscience Research Institute

Faculty Biosketch

Milton S. Hershey Medical Center
Penn State College of Medicine
P.O. Box 850, 
500 University Drive
Hershey, PA 17033-2390

Joan Summy-Long, Ph.D.

Department of Pharmacology
 

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Office Information

Phone: 717-531-8290
Mail Code: H078

Education
B.S., Biology, Bucknell University, 1965
Ph.D., (& M.S.) Penn State College of Medicine, 1978 (1972)

Sabbatical at the State University of New York at Stony Brook Laboratory of Jeffrey White, Ph.D., Department of Endocrinolgy

Primary Area of Interest
Neurobiology of dendritic release of neuropeptides, interleukin 1-B and nitric oxide in the magnocellular system..
Research Focus
The magnocellular neuroendocrine system is comprised of neurons in the hypothalamus that synthesize and release oxytocin (OT) or vasopressin (VP) from their dendrites in the supraoptic nuclei (SON) and axon terminals in the neural lobe to physiologically regulate hydration and reproduction. Dendritically released OT (and VP) modulates incoming neural traffic as well as promotes the morphological plasticity of magnocellular neurons. Dendritic release from magnocellular neurons may also be a source of interleukin 1-B (IL-1B) or a target of its modulation. Supporting this hypothesis, IL-1B, as well as NO synthase (NOS; figure 1), are present in magnocellular neurons and have been shown responsive to dehydration. Our research demonstrates that cytokine in both the SON and neural lobe responds in a parallel manner to changes in neurohypophysial hormones during dehydration. Specifically, in the neural lobe, rats drinking 2% NaCl for 2 to 8 days had a progressive co-depletion of cytokine and neurophyophysial hormones (figure 2), when expression of NOS and the IL-1receptor type I becomes enhanced as reported by others. Similarly, dendritic release of OT and VP in response to an acute osmotic stimulation is paralleled by a corresponding rise in cytokine levels in microdialysates of the SON area (figure 3) by a mechanism requiring neural function (tetrodotoxin-sensitive) and voltage-gated calcium channels (figure 4). Preliminary data demonstrate that microglia in the SON area become activated during microdialysis (figure 5) and thereby release IL-1B under “basal” conditions whereas magnocellular dendrites may corelease cytokine with OT and VP during osmotic stimulation. Our current research focuses on clarifying functional interactions of magnocellular neurons with adjacent microglia and their role in regulating dendritic release of OT and VP. Contrasting the neurobiology of IL-1B and NO in the magnocellular system with their pro-inflammatory actions as mediators of the immune system will potentially achieve
References
1.Kadekaro M, Harris J, Freeman S, Terrell Ml, Koehler E, Summy-Long JY. Water intake and activity of the hypothalamo-neurohypophysial system during osmotic and sodium stimulation in rats. Am J Physiol 268 (Regulatory Integrative Comp Physiol 37):R651-R657.

2.Liu H, Terrell ML, Summy-Long JY, Kadekaro M. Drinking and blood pressure responses to central injection of L-NAME in conscious rats. Physiol Behav 1996; 59(6):1137-1146.

3. Summy-Long JY, Gestl S, Terrell ML, Wolz G, Kadekaro M. Osmoregulation of the magnocellular neuroendocrine system during lactation. Am J Physiol 1997; 272 (Regulatory Integrative Comp. Physiol. 41):R275-R288.

4. Liu H, Terrrell ML, Bui V, Summy-Long JY, Kadekaro M. NO and angiotensin II effects on blood pressure and fluid homeostasis. J Neuroendocrinol 1997; 9:545-552.

5. Kadekaro M, Liu H, Terrell ML, Gestl S, Bui V, Summy-Long JY. Role of NO on vasopressin and oxytocin release and blood pressure responses during osmotic stimulation in rats. Am J Physiol 1997; 273(3 Pt 2):R1024-R1030.

6. Koehler-Stec EM, Byers A, Summy-Long JY. Effects of chronic central infusion of oxytocin on the response of the magnocellular neuroendocrine system to osmotic stimulation. Pharmacology 1998; 56(2):101-110.

7. Summy-Long JY, Bui V, Gestl S, Koehler-Stec E, Liu H, Terrell ML, Kadekaro M. Effects of central injection of kyotorphin and L-arginine on oxytocin and vasopressin release and blood pressure in conscious rats. Brain Res Bull 1998; 45(4):395-403.

8. Kadekaro M, Terrell ML, Liu H, Gestl S, Bui V, Summy-Long JY. Effects of L-NAME on cerebral metabolic, vasopressin, oxytocin, and blood pressure responses in hemorrhaged rats. Am J Physiol 1998; 274(4 Pt 2):R1070-1077.

9. Liu H, Terrell ML, Summy-Long JY, Kadekaro M. Brain ANG II and prostaglandins mediate the pressor response after central blockade of nitric oxide synthase. Brain Res 1998; 785(2):317-328.

10. Liu H, Terrell ML, Bui V, Summy-Long JY, Kadekaro M. Nitric oxide control of drinking, vasopressin and oxytocin release and blood pressure in dehydrated rats. Physiol Behav 1998; 63(5):763-769.

11. Brind J, Chinchilli VM, Severs WB, Summy-Long J. Correcting the Record on Abortion and Breast Cancer. Breast J 1999; 5(3):215-216.

12. Summy-Long JY, Kadekaro M. Reponses and adaptations of the magnocellular neuroendocrine system to stress. In: Control Mechanisms of Stress and Emotion: Neuroendocrine-Based Studies, Excerpta Medica International Congress Series II85, Eds. Yamashit H, Funder JW, Verbalis JG, Ueta Y, Endo Y, Elsevier Science 1999; pp. 185-199.

13. Kadekaro M, Summy-Long JY. Nitric oxide modulation of body fluid and blood pressure homeostasis during stress. In: Control Mechanisms of Stress and Emotion: Neuroendocrine-Based Studies, Excerpta Medica International Congress Series II85, Eds. Yamashita H, Funder JW, Verbalis JG, Ueta Y, Endo Y, Elsevier Science, 1999; pp. 199-212.

14. Kadekaro M, Summy-Long JY. Centrally produced nitric oxide and the regulation of body fluid and blood pressure homeostases. Clin Exp Pharmacol Physiol 2000; 27(5-6):450-459.

15. Kadekaro M, Terrell ML, Liu H, Bui V, Summy-Long JY. Indomethacin prevents the L-NAME-induced increase in plasma levels of oxytocin in dehydrated rats. Brain Res 2000; 877(2):371-373.

16. Kershenovich A, Terrell ML, Summy-Long JY, Kadekaro M. Angiotensin II does not mediate the pressor response to PGD2 (icv). J Renin Angiotensin Aldosterone Syst 2000; 1(2):196-201.

17. Summy-Long JY, Kadekaro M. Role of circumventricular organs (CVO) in neuroendocrine responses: interactions of CVO and the magnocellular neuroendocrine system in different reproductive states. Clin Exp Pharmacol Physiol 2001; 28(7):590-601.

18. Kadekaro M, Terrell ML, Bui V, Summy-Long JY. Central interactions between angiotensin II and PGD(2) in the regulation of vasopressin and oxytocin secretion in dehydrated rats. Brain Res 2001; 889(1-2):84-88.

19. Summy-Long JY, Bui V, Gestl S, Kadekaro M. Nitric oxide, interleukin and prostaglandin interactions affecting the magnocellular system. Brain Res 2002; 940(1-2):10-20.

20. Terrell ML, Salas N, Bui V, Summy-Long JY, Kadekaro M. NO inhibition of the magnocellular neuro-endocrine system in rats is independent of cGMP signaling pathway. Exp Neurol 2003; 184(2):846-856.

21. Salas N, Terrell ML, Summy-Long JY, Kadekaro M. Role of prostaglandin, endothelin and sympathetic nervous system on the L-NAME-induced pressor responses in spontaneously hypertensive rats. Brain Res 2003; 983(1-2):162-173.

22. Hadsell DL, Bonnette S, George J, Torres D, Klementidis Y, Gao S, Haney PM, Summy-Long J, Soloff MS, Parlow AF, Sirito M, Sawadogo M. Diminished milk synthesis in upstream stimulatory factor 2 null mice is associated with decreased circulating oxytocin and decreased mammary gland expression of eukaryotic initiation factors 4E and 4G. Mol Endocrinol 2003; 17(11):2251-2267.

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