Neuroscience 2000 Abstract
| Presentation Number: | 569.19 |
|---|---|
| Abstract Title: | Dysfunctional glucose sensing in the ventromedial hypothalamic nucleus of diet induced obesity-prone rats. |
| Authors: |
Routh, V. H.*1
; Levin, B. E.2,3
; Song, Z.1
1Pharm. & Physiol., NJ Med Sch , Newark, NJ 2Neurosci., NJ Med Sch , Newark, NJ 3Neurol. Serv., VAMC, E. Orange, NJ |
| Primary Theme and Topics |
I. Neural Basis of Behavior - 115. Ingestive behaviors |
| Secondary Theme and Topics | E. Endocrine and Autonomic Regulation<br />- 64. Neuroendocrine regulation: other |
| Session: |
569. Ingestive behaviors: metabolic regulators Poster |
| Presentation Time: | Tuesday, November 7, 2000 3:00 PM-4:00 PM |
| Location: | Hall G-J |
| Keywords: | synaptic transmission, brain slices, electrophysiology, KATP channel |
VMN glucosensing neurons alter their firing rate in response to physiologic changes in extracellular glucose. This is mediated in part by the ATP-sensitive K+ (KATP) channel (Routh et al., SFN Abst 25:416, 99) which we found to be defective in inbred DIO-prone vs DR rats (Routh et al., FASEB J. 12(5) A864, 98). To assess whether glucosensing by intact VMN neurons in DIO-prone rats is also dysfunctional, 350 micron slices through the VMN of 14-21d inbred DIO and DR rats were perfused with artificial CSF + 2.5 mM glucose. Current clamp measurements were made using conventional whole cell patch clamp with ATP (2 mM) included in the patch pipette. Decreasing extracellular glucose from 2.5 to 0.1 mM either increased (11 of 52) or decreased (8 of 52) the firing rate of 36% of VMN neurons in DR rats. The latter was reversed by 200 μM tolbutamide (n = 4), suggesting involvement of the KATP channel. Similarly, increasing extracellular glucose from 2.5 to 5 or 10 mM glucose either increased (8 of 42) or decreased (6 of 42) the firing rate of 33% of VMN neurons in these rats. In contrast, only 16% of VMN neurons from DIO-prone rats either increased (3 of 38) or decreased (3 of 38) their firing rate when extracellular glucose was decreased from 2.5 to 0.1 mM. Likewise, the firing rate of only 7% of VMN neurons in DIO-prone rats either increased (1 of 28) or decreased (1 of 28) when extracellular glucose was raised from 2.5 to 5 or 10 mM. This suggests that VMN glucosensing neurons are dysfunctional in DIO-prone rats.
Supported by ADA Career Dev. Award; RO1DK53181
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2000 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2000. Online.
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