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APS Neurohypophyseal Conference 

APS Neurohypophyseal Hormone Oxytocin/Vasopressin Conference:
Highlights Of Presentations From Autism And Voles, Endocannabinoids And Stress, To Hormonal Signaling: Radical Shift In Brain Processin

STEAMBOAT SPRINGS, Colorado – The American Physiological Society conference on the neurohypophyseal hormones oxytocin and vasopressin is being held July 16-20. Below are thumbnail sketches of 13 presentations combined into nine subject areas. The full press releases are available on the APS Press Room conference website:

http://www.the-aps.org/press/conference/index.htm

Larry Young on animals and autism clues, environmental impact on hormone brain function

Young began studying voles for their monogamous behavior, then investigated molecular mechanisms in species behavior differences. Now researchers are gaining insights into human disorders with social impairments like autism. Keynoting an APS conference on oxytocin/vasopressin Young points to studies confirming their roles in social cognition and suggesting a developmental role for oxytocin in shaping normal adult social behavior. He strongly advocated observing nature for new animal behavioral and physiological models to further research.

“Oxytocin, vasopressin and social cognition: Implications for Autism,” was presented as the closing keynote address by Larry Young.

Hormonal signaling in the brain: radical shift in understanding information processing

University of Edinburgh researchers say our understanding of how the brain processes information is undergoing a radical shift as we recognize the implications of hormonal signaling systems within the brain itself. Using the concept of the OT-VP plexus as an "endocrine gland" in the brain, whereby oxytocin released centrally from dendrites "triggers a cascade of temporary functional reorganization of specific neuronal networks, providing the substrate for prolonged behavioral effects." Example: Alpha-MSH and male sexual behavior.

“Melanocortin and oxytocin in facilitated sexual responses.” Gareth Leng, Celine Caquineau, Nancy Sabatier, Alison Douglas; University of Edinburgh.

“Mechanisms underlying independent release of dendritic and neurohypophyseal oxytocin and vasopressin release.” Mike Ludwig, University of Edinburgh. Funded by Wellcome Trust and BBSRC (U.K. Office of Science & Technology’s Biotechnology and Biological Sciences Research Council).

OT, VP studied as novel psychiatric drug sources; consider gender-specific drug models

Wyeth Neuroscience says evidence is growing about the "important role of oxytocin in the neurophysiology underlying anxiety and schizophrenia." Oxytocin and vasopressin act as powerful neurotransmitters, regulating many brain functions that are often disturbed in psychiatric disease, a senior researcher added, and "novel treatments for such psychiatric diseases might be developed." The male-female dimorphisms in both the OT/VP systems and differences in psychiatric disease incidence make a case for considering gender-targeted therapies.

“The central vasopressinergic and oxytocinergic systems as targets for psychiatric

drug development.” Robert H. Ring, Head of Molecular Neurobiology, Depression & Anxiety Disorders, Discovery Neuroscience, Wyeth Research, Princeton, New Jersey. 

Choline during pregnancy may avoid, reverse some Fetal Alcohol Syndrome nervous disorders

Tripler Army MedCenter researchers showed that including choline in pre-natal diets of rats avoided symptoms of prenatal alcohol in young adult animals. They also believe they've identified several physiological approaches that could lead to post-natal screening methods to identify babies with possible FAS or related diseases. These include monitoring urine flow and its vasopressin content. They also found some indication, or at least possible correlation, that vasopressin could serve some function in cognitive development.

“Amelioration of fetal alcohol-induced diabetes insipidus by dietary choline during pregnancy in the rat.”  John Claybaugh, Ginger Pole, Aileen Sato, Danielle Bird, Catherine Uyehara, Tripler Army Medical Center, Honolulu.  Funded in part by Hawaii Community Foundation and Clinical Research Center.

GSK nonpeptide oxytocin receptor antagonists damp contractions in late-term rat pregnancy

"Delaying labor with an oxytocin receptor antagonist may significantly reduce infant morbidity, including lung disease, intraventricular hemorrhage, and possibly even death," a GlaxoSmithKline Pharmaceuticals lead researcher said. He noted that GSK researchers have developed several non-peptide selective oxytocin receptor antagonists that have a high affinity for the human and rat OT receptors. He reported that these compounds suppressed spontaneous contractions in late-term pregnant rats. Short gestation/low birth weight is the second-leading cause of infant death.

David P. Brooks, Vice President Biology U.S., Cardiovascular and Urogenital Drug Discovery Centre, GlaxoSmithKline Pharmaceuticals, King of Prussia, Penn. “Develop- ment of non-peptide oxytocin receptor antagonists for the treatment of preterm labor.”

Endocannabinoids – the brain's cannabis – demonstrate novel modes of action to stress

Research teams from Louisiana, Japan and Scotland report on endocannabinoids as a novel neural messenger in various stress-related situations with possible applications in eating, disease treatment and social behavior. Led by Shi Di, the Tulane/LSU team found that endocannabinoids acted as an intrabrain messenger to shutdown the neuroendocrine stress response. The Japanese team, headed by Atsushi Soya, said it next would look at endocannabinoids involvement in autonomic, endocrine and immune function. The Edinburgh group led by Nancy Sabatier is studying endocannabinoids' influence on oxytocin and social behavior.

“Rapid glucocorticoid-mediated endocannabinoid release and opposing regulation of glutamate and GABA inputs to hypothalamic magnocellular neurons.”  Funded by NIH.

   Shi Di, Victor Marcheselli, Nicolas Bazan, Jeffrey Tasker. Di and Tasker are at the Neurobiology Division and Cell & Molecular Biology Department at Tulane University, New Orleans; Tasker is also at the Neuroscience Program;  Marcheselli and Bazan are at the Neuroscience Center, Louisiana State University Health Sciences Center, New Orleans.

“Cannabinoid modulates synaptic inputs to the supraoptic nucleus neuron in rats.”

   Atsushi Soya, Ryota Serino, Tatsushi Onaka, Takeshi Terao, Jun Nakamura, Yoichi Ueta.

Soya and Ueta are at Dept. of Physiology School of Medicine, University of Occupational & Environmental Health (UOEH), Kitakyushu; Serino is at the UOEH Dept. of Internal Medicine; Onaka is at Division of Integrative Physiology, Dept. of Physiology, Jichi Medical School; Terao is at Dept. of Psychiatry, Oita University School of Medicine; and Nakaura is at UOEH Dept. of Psychiatry.

 “Cannabanoids inhibit excitatory responses of supraoptic neurons to stimulation of OVLT in vivo.” Nancy Sabatier, Gareth Leng, University of Edinburgh, Scotland.

Oxytocin raises aggression, cuts anxiety during lactation; similar effects on virgin rats

Maternal aggressive/protective behavior is recognized throughout mammalian species, especially during lactation. The same neurohypophyseal hormone, oxytocin, is responsible for both the physiological and behavioral changes, but the site of action is different. OT within the brain has marked behavioral impact, including reducing anxiety levels during lactation. Regensburg/Edinburgh University researchers directly inserted OT into the brain of virgin rats causing lower anxiety and increased social dominance. Also: A model to determine OT regulation at birth.

“Oxytocin release within the brain: physiological and behavioral consequences in lactation.”  Inga D. Neumann, Martin Waldherr, Daniela Beiderbeck and Oliver Bosch, Institute of Zoology, University of Regensburg, Germany; Alison J. Douglas, University of Edinburgh; Larry Young, Emory University. Funded by Volkswagen Foundation and DAAD (German academic exchange) (Neumann); NSF (Young); British Council (Douglas).

“Evaluation of the role of central noradrenaline in activating oxytocin neurons at parturition.” Alison J. Douglas, Alex Gillies, Vicky Briam, Simone Meddle, Neuroendocrinology, Centre for Integrative Physiology, University of Edinburgh, Scotland. Funded by Wellcome Trust.

If oxytocin eating role doesn't mature at birth, what other situations affect its impact?

Pittsburgh researchers taking a developmental approach on OT modulation of eating and digestion, found OT contributes to dehydration inhibiting food intake in mature rats and mice, but not baby rats. Plus, 'dehydration anorexia' is absent in OT-null mice who ate regularly when dehydrated, indicating OT is key signaling peptide in hypothalamic control of adaptive responses to dehydration. By pinpointing when OT impacts ingestion, they'll learn how OT and other peptides function under unique environmental conditions.

“Oxytocin and ingestive behavior.” Linda Rinaman, University of Pittsburgh. Funding: NIH grant.

Would boosting the oxytocin system lead to longer breast-feeding?

The benefits of breastfeeding infants over giving them formula are well-known. But a baby's slow weight gain and growth rate is a major reason many women stop. University of Utah researchers found that blocking central OT receptors in the pregnant females' brain reduced their offspring's growth from the third day after birth through their two-week experiment. They're now seeking ways to boost efficiency of the oxytocin system.

“Central oxytocin receptor blockade during gestation alters oxytocin release and pup development during lactation.” Steven L. Bealer, William R. Crowley, David L. Lipschitz, University of Utah. Funded by U.S. Public Health Service grants.

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Editors note: The presentations above were given at the American Physiological Society’s 2005 Conference, “Neurohypophyseal Hormones: From Genomics and Physiology to Disease,” July 16-20 in Steamboat Springs, Colorado. 

A detailed program, including abstracts, for the entire meeting is available to members of the media at:

http://www.the-aps.org/publications/tphys/images/JuneTphysConferenceMaterial.pdf

Arrangements for interviews can be through APS from Donna Krupa (cell: 301.332.4402; office (301) 634-7209, or dkrupa@the-aps.org).

Sponsorships. The American Physiological Society thanks the following sponsors for their generous support of the conference: Astellas Pharmaceuticals Inc., GlaxoSmithKline Pharmaceuticals, NIH/NIDDK, Wyeth Research and Olympus America Inc.

Three APS Journals call for papers. In conjunction with the conference, three American Journal of Physiology (AJP) editions – AJP-Regulatory, Integrative and Comparative Physiology, AJP-Endocrinology and Metabolism, and AJP-Renal Physiology – have called for related papers for publication. The deadline for all editions is October 1, 2005.

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The American Physiological Society was founded in 1887 to foster basic and applied bioscience. The Bethesda, Maryland-based society has more than 10,000 members and publishes 14 peer-reviewed journals containing almost 4,000 articles annually. 

APS  provides a wide range of research, educational and career support and programming to further the contributions of physiology to understanding the mechanisms of diseased and healthy states. In May 2004, APS received the Presidential Award for Excellence in Science, Mathematics and Engineering Mentoring (PAESMEM).

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