Neuroscience 2001 Abstract
| Presentation Number: | 947.5 |
|---|---|
| Abstract Title: | DIFFERENTIAL EFFECTS OF LACTATE ON GLUCOSENSING NEURONS IN THE VENTROMEDIAL HYPOTHALAMIC NUCLEUS (VMN). |
| Authors: |
Song, Z.*1
; Routh, V. H.1
1Pharmacol. & Physiol., NJ Med School, Newark, NJ |
| Primary Theme and Topics |
Autonomic, Limbic and Other Systems - Regulation of Food Intake and Body Weight |
| Session: |
947. Regulation of food intake and body weight III Poster |
| Presentation Time: | Thursday, November 15, 2001 8:00 AM-9:00 AM |
| Location: | Exhibit Hall PP-8 |
| Keywords: | Glucose, Glucose responsive neuron, Brain slice, Patch clamp |
The VMN is a key site for regulating energy balance. We previously found several subtypes of VMN glucosensing neurons which respond to physiologic changes in extracellular glucose. Glucose responsive (GR) and glucose sensitive (GS) neurons were directly inhibited or excited, respectively, when extracellular glucose levels were decreased from 2.5 to 0.1 mM. In contrast, other VMN neurons (PED neurons) were presynaptically excited when extracellular glucose was decreased from 2.5 to 0.1 mM (Song et al., SFN Abst.26: 2219, 2000). It is not known whether these glucosensing neurons are uniquely sensitive to changes in glucose or whether they respond to other energy substrates used by the brain. Recent evidence indicates that the brain derives a significant portion of its energy from lactate. Thus, this study was performed to determine whether lactate could reverse the effects of decreasing extracellular glucose on VMN glucosensing neurons. 350 μm slices were sectioned through the VMN of the brains of 14-21 d Sprague-Dawley rats. Slices were then perfused with artificial CSF + 2.5 mM glucose. Current clamp recordings were made using conventional whole cell recording. GR neurons hyperpolarized and decreased their firing rate as extracellular glucose decreased from 2.5 to 0.1 mM. Lactate (0.5 mM) in the presence of 0.1 mM glucose restored the firing rate of GR neurons to control levels. In contrast 5 mM lactate did not reverse the excitatory effect of 0.1 mM glucose on PED neurons. These data suggest that while PED neurons are specifically regulated by glucose, GR neurons are sensitive to other energy substrates which alter intracellular metabolism.
Supported by RO1 DK55619-01A1
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2001 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2001. Online.
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