Abstract
In urethane/α-chloralose anesthetized rats, cold exposure increased brown adipose tissue sympathetic nerve activity (BAT SNA: +699 ± 104% control). Intravenous administration of 2-deoxy-d-glucose (2-DG; 200 mg·ml -1·kg -1) reversed the cold-evoked activation of BAT SNA (nadir: 139 ± 36% of control) and decreased BAT temperature (-1.1 ± 0.2°C), expired CO 2 (-0.4 ± 0.1%), and core temperature (-0.5 ± 0.0). Similarly, unilateral nanoinjection of the glucoprivic agent 5-thioglucose (5-TG; 12 μg/100 nl) in the ventrolateral medulla (VLM) completely reversed the cold-evoked increase in BAT SNA (nadir: 104 ± 7% of control), and decreased T BAT (-1.4 ± 0.3°C), expired CO 2 (-0.2 ± 0.0%), and heart rate (-35 ± 10 beats/min). The percentage of rostral raphé pallidus (RPa)-projecting neurons in the dorsal hypothalamic area/dorsomedial hypothalamus that expressed Fos in response to cold exposure (ambient temperature: 4-10°C) did not differ between saline (28 ± 6%) and 2-DG (30 ± 5%) pretreated rats, whereas the percentage of spinally projecting neurons in the RPa/raphé magnus that expressed Fos in response to cold exposure was lower in 2-DG- compared with saline-pretreated rats (22 ± 6% vs. 42 ± 5%, respectively). The increases in BAT SNA evoked by nanoinjection of bicuculline in the RPa or by transection of the neuraxis at the pontomedullary border were resistant to inhibition by glucoprivation. These results suggest that neurons within the VLM play a role in the glucoprivic inhibition of BAT SNA and metabolism, that this inhibition requires neural structures rostral to the pontomedullary border, and that this inhibition is mediated by a GABAergic input to the RPa.
| Original language | English (US) |
|---|---|
| Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
| Volume | 302 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jan 2012 |
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Keywords
- 2-DG
- CVLM
- Hypoglycemia
- Metabolism
- RVLM
- Thermoregulation
ASJC Scopus subject areas
- Physiology
- Physiology (medical)
Cite this
Glucoprivation in the ventrolateral medulla decreases brown adipose tissue sympathetic nerve activity by decreasing the activity of neurons in raphé pallidus. / Madden, Christopher (Chris).
In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 302, No. 2, 01.2012.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Glucoprivation in the ventrolateral medulla decreases brown adipose tissue sympathetic nerve activity by decreasing the activity of neurons in raphé pallidus
AU - Madden, Christopher (Chris)
PY - 2012/1
Y1 - 2012/1
N2 - In urethane/α-chloralose anesthetized rats, cold exposure increased brown adipose tissue sympathetic nerve activity (BAT SNA: +699 ± 104% control). Intravenous administration of 2-deoxy-d-glucose (2-DG; 200 mg·ml -1·kg -1) reversed the cold-evoked activation of BAT SNA (nadir: 139 ± 36% of control) and decreased BAT temperature (-1.1 ± 0.2°C), expired CO 2 (-0.4 ± 0.1%), and core temperature (-0.5 ± 0.0). Similarly, unilateral nanoinjection of the glucoprivic agent 5-thioglucose (5-TG; 12 μg/100 nl) in the ventrolateral medulla (VLM) completely reversed the cold-evoked increase in BAT SNA (nadir: 104 ± 7% of control), and decreased T BAT (-1.4 ± 0.3°C), expired CO 2 (-0.2 ± 0.0%), and heart rate (-35 ± 10 beats/min). The percentage of rostral raphé pallidus (RPa)-projecting neurons in the dorsal hypothalamic area/dorsomedial hypothalamus that expressed Fos in response to cold exposure (ambient temperature: 4-10°C) did not differ between saline (28 ± 6%) and 2-DG (30 ± 5%) pretreated rats, whereas the percentage of spinally projecting neurons in the RPa/raphé magnus that expressed Fos in response to cold exposure was lower in 2-DG- compared with saline-pretreated rats (22 ± 6% vs. 42 ± 5%, respectively). The increases in BAT SNA evoked by nanoinjection of bicuculline in the RPa or by transection of the neuraxis at the pontomedullary border were resistant to inhibition by glucoprivation. These results suggest that neurons within the VLM play a role in the glucoprivic inhibition of BAT SNA and metabolism, that this inhibition requires neural structures rostral to the pontomedullary border, and that this inhibition is mediated by a GABAergic input to the RPa.
AB - In urethane/α-chloralose anesthetized rats, cold exposure increased brown adipose tissue sympathetic nerve activity (BAT SNA: +699 ± 104% control). Intravenous administration of 2-deoxy-d-glucose (2-DG; 200 mg·ml -1·kg -1) reversed the cold-evoked activation of BAT SNA (nadir: 139 ± 36% of control) and decreased BAT temperature (-1.1 ± 0.2°C), expired CO 2 (-0.4 ± 0.1%), and core temperature (-0.5 ± 0.0). Similarly, unilateral nanoinjection of the glucoprivic agent 5-thioglucose (5-TG; 12 μg/100 nl) in the ventrolateral medulla (VLM) completely reversed the cold-evoked increase in BAT SNA (nadir: 104 ± 7% of control), and decreased T BAT (-1.4 ± 0.3°C), expired CO 2 (-0.2 ± 0.0%), and heart rate (-35 ± 10 beats/min). The percentage of rostral raphé pallidus (RPa)-projecting neurons in the dorsal hypothalamic area/dorsomedial hypothalamus that expressed Fos in response to cold exposure (ambient temperature: 4-10°C) did not differ between saline (28 ± 6%) and 2-DG (30 ± 5%) pretreated rats, whereas the percentage of spinally projecting neurons in the RPa/raphé magnus that expressed Fos in response to cold exposure was lower in 2-DG- compared with saline-pretreated rats (22 ± 6% vs. 42 ± 5%, respectively). The increases in BAT SNA evoked by nanoinjection of bicuculline in the RPa or by transection of the neuraxis at the pontomedullary border were resistant to inhibition by glucoprivation. These results suggest that neurons within the VLM play a role in the glucoprivic inhibition of BAT SNA and metabolism, that this inhibition requires neural structures rostral to the pontomedullary border, and that this inhibition is mediated by a GABAergic input to the RPa.
KW - 2-DG
KW - CVLM
KW - Hypoglycemia
KW - Metabolism
KW - RVLM
KW - Thermoregulation
UR - http://www.scopus.com/inward/record.url?scp=84855323734&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84855323734&partnerID=8YFLogxK
U2 - 10.1152/ajpregu.00449.2011
DO - 10.1152/ajpregu.00449.2011
M3 - Article
VL - 302
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 2
ER -