[Abstract Title]. - Society for Neuroscience

neurons that are defined by their expression of melanin concentrating hormone (MCH) and
orexin (OX); the LHA also contains a distinct population of LepRb-expressing neurons. In order
to understand the LepRb-expressing neural afferents of LHA neurons, we generated and
employed several novel adenoviral and transgenic systems in which cre recombinase promotes
the expression of the anterograde tracer, wheat germ agglutinin (WGA), or the retrograde tracer,
tetanus toxin C (TTC). Utilizing these systems in conjunction with LepRb cre mice initially
demonstrated the direct innervation of both MCH and OX neurons by anatomically undefined
groups of LepRb neurons, and revealed the synaptic coupling of OX, but not MCH neurons with
LHA LepRb neurons. Using the trans-synaptic tracers in combination with ARC-specific Pomc cre
and Agrp cre mice demonstrated that these ARC LepRb neurons directly innervate both OX and
MCH neurons, but not LHA LepRb neurons. The use of these novel neuroanatomical tracing
tools permits the analysis of the synaptic connectivity of distinct populations of intermingled
neurons, and has revealed the mechanisms by which specific groups of LepRb neurons modulate
distinct aspects of LHA physiology.
Disclosures: G.W. Louis, None; G.M. Leinninger, None; C.J. Rhodes, None; M.G. Myers,
None.
Poster
284. Regulation of Food Intake and Body Weight: Integration of Peripheral Signals:
Systems
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 284.18/QQ13
Topic: E.07.b. Integration of peripheral signals: Systems
Support: NIH grant DK065971
Title: Fasting reduces vomiting in the musk shrew
Authors: *C. C. HORN 1 , C. E. FITZGERALD 2 , M. I. FRIEDMAN 1 ;
1 Monell Chem. Senses Ctr., Philadelphia, PA; 2 Univ. of Pennsylvania, Phildadelphia, PA
Abstract: Nausea and vomiting are systems that protect the body from ingested toxins. These
symptoms are ubiquitous in clinical care and treatment, including stimulation by various
medicines (cancer chemotherapy drugs, anesthetics, opioids), pregnancy, and radiotherapy, but
the neurobiology of these processes is not well understood. The neural system for emesis is
generally considered to be a “hard-wired” reflex that is determined by the strength of the
stimulus. Prior reports show that appetite stimulants (ghrelin and endocannabinoids) can reduce
emesis in laboratory animals, suggesting that stimulation of feeding can modulate emesis. Here