scholarly journals GABA-mediated inhibition of raphe pallidus neurons regulates sympathetic outflow to brown adipose tissue

1999 ◽  
Vol 276 (2) ◽  
pp. R290-R297 ◽  
Author(s):  
Shaun F. Morrison ◽  
Alan F. Sved ◽  
Alicia M. Passerin
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Burst Frequency ◽  
Nerve Activity ◽  
Brown Adipose ◽  
Reflex Activation ◽  
Raphe Pallidus ◽  
Nerve Discharge

Sympathetic nerve activity to brown adipose tissue (BAT) regulates adipocyte metabolism of its stored lipid fuel and thus the thermogenesis in BAT. To determine if the discharge of neurons in the rostral raphe pallidus (RPa) can influence BAT thermogenesis, changes in sympathetic nerve activity to BAT were recorded after microinjection (60 nl) of the GABAA receptor antagonist bicuculline (500 μM) into the RPa in chloralose-urethan-anesthetized, ventilated rats. Bicuculline caused a large, rapid rise in the sympathetic nerve activity to BAT (which had also increased during acute hypothermia) from very low, normothermic control levels to maximum values (mean: 1,949 ± 604% control; n = 13) after 4–6 min. The sympathetic nerve discharge to BAT had a mean burst frequency (3.5 ± 0.3 Hz) that was significantly less than the heart rate (7.3 ± 0.2 beats/min), and it was not inhibited during baroreceptor reflex activation. Bicuculline-stimulated increases in the sympathetic nerve activity to BAT and cold-evoked increases in neuronal fos expression were localized to the RPa at the level of the caudal half of the facial nucleus. This dramatic increase in sympathetic nerve activity to BAT after disinhibition of neurons in rostral RPa is consistent with a major role for RPa neurons, perhaps as sympathetic premotoneurons for BAT, in medullary control of BAT thermogenesis.

scholarly journals Glucoprivation in the ventrolateral medulla decreases brown adipose tissue sympathetic nerve activity by decreasing the activity of neurons in raphé pallidus

2012 ◽  
Vol 302 (2) ◽  
pp. R224-R232 ◽  
Author(s):  
C. J. Madden
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Cold Exposure ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Ventrolateral Medulla ◽  
Nerve Activity ◽  
Hypothalamic Area ◽  
Brown Adipose ◽  
Raphe Pallidus

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 CO2 (−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 TBAT (−1.4 ± 0.3°C), expired CO2 (−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.

Effect of beta-endorphin on sympathetic nerve activity to interscapular brown adipose tissue

1993 ◽  
Vol 264 (1) ◽  
pp. R109-R115 ◽  
Author(s):  
M. Egawa ◽  
H. Yoshimatsu ◽  
G. A. Bray
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Intracerebroventricular Injection ◽  
Nerve Activity ◽  
Reciprocal Effect ◽  
Interscapular Brown Adipose Tissue ◽  
Beta Endorphin ◽  
Brown Adipose

beta-Endorphin was injected into the third cerebroventricle to investigate its effects on sympathetic nerve activity to interscapular brown adipose tissue (IBAT) in rats. Multiunit discharges of sympathetic nerves to IBAT were recorded electrophysiologically in anesthetized rats. The intracerebroventricular injection of beta-endorphin (125, 250, and 500 pmol/rat in 10 microliters) suppressed sympathetic nerve activity in a dose-related fashion (-23.9 +/- 20.4, -38.7 +/- 7.1, and -66.7 +/- 7.6% 30 min after injection) compared with preinjection baseline. N-acetyl-beta-endorphin (250 pmol) had no effect on sympathetic nerve activity to IBAT. The intraperitoneal injection of naloxone (5.0 mg/rat) did not affect sympathetic nerve activity, but preinjection of naloxone inhibited the suppressive effect of intracerebroventricular injection of beta-endorphin (250 pmol). We conclude that the intracerebroventricular administration of beta-endorphin suppressed the sympathetic nerve activity to IBAT through opioid receptors. The results of this experiment are consistent with the hypothesis that beta-endorphin has a reciprocal effect on food intake and the sympathetic nervous system.

scholarly journals Dual Regulatory Effects of Orexins on Sympathetic Nerve Activity Innervating Brown Adipose Tissue in Rats

Endocrinology ◽  
2005 ◽  
Vol 146 (6) ◽  
pp. 2744-2748 ◽  
Author(s):  
Tohru Yasuda ◽  
Takayuki Masaki ◽  
Tetsuya Kakuma ◽  
Masahide Hara ◽  
Tomoko Nawata ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Histidine Decarboxylase ◽  
Cerebral Ventricle ◽  
Induced Response ◽  
Nerve Activity ◽  
Orexin A ◽  
Brown Adipose

Abstract This study examined how orexin regulates the activity of the sympathetic nerves that innervate brown adipose tissue (BAT) in rats. Infusion of orexin A at a dose of 0.3 nmol into the third cerebral ventricle decreased BAT sympathetic nerve activity, compared with the effect of PBS (P < 0.05), whereas infusion of orexin B at the same dose caused a significant increase (P < 0.05). Pretreatment with a third cerebral ventricle injection of 2.24 μmol/kg α-fluoromethylhistidine, an irreversible inhibitor of the histamine-synthesizing enzyme histidine decarboxylase, attenuated the orexin B-induced response of BAT sympathetic nerve activity, but not that induced by orexin A. These results indicate that orexins may regulate both BAT energy expenditure and thermogenesis through their dual effects on sympathetic nerve activity. In particular, orexin B regulates BAT sympathetic nerve activity via neuronal histamine in the hypothalamus.

Effects of central injection of l-carnosine on sympathetic nerve activity innervating brown adipose tissue and body temperature in rats

2007 ◽  
Vol 144 (1-3) ◽  
pp. 62-71 ◽  
Author(s):  
Mamoru Tanida ◽  
Hitoshi Gotoh ◽  
Hiroyuki Taniguchi ◽  
Hiroto Otani ◽  
Jiao Shen ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Body Temperature ◽  
Brown Adipose Tissue ◽  
Sympathetic Nerve ◽  
Sympathetic Nerve Activity ◽  
Nerve Activity ◽  
Brown Adipose
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