VSG Maintenance Group
The biochemistry of compulsive eating
There was a similar story on last nights news, Diane Sawyer's program, about how genuinely addictive food is and how it triggered the same brain mechanisms as other addictive substances, or something like that. It is comforting to know things like this because from an early age many of us are shamed for our desires to overeat and filled with self loathing because we do and can't seem to control our eating impulses. I have no doubt that with wls something changes in brain chemestry even if it is just due to gettiing off the sugar and carbs or whatever the issue is.
Anyway, might check on line at whatever network Diane Sawyer is on to see if there is a clip or story.
If anybody has a link or citation to these studies, post it. Even for us non profesionals its interesting to understand the science.
Diane
Anyway, might check on line at whatever network Diane Sawyer is on to see if there is a clip or story.
If anybody has a link or citation to these studies, post it. Even for us non profesionals its interesting to understand the science.
Diane
Join US On The VSG Maintenance Group Forum!!
http://www.obesityhelp.com/group/VSGM/discussion/
There are plenty of studies out there, but I was curious to see if there was anything published about WLS patients specifically.
I found 2 recent studies, but the results contradict each other, most likely due to small sample sizes. and that's half of the battle of research for you. :) This is the particular dopamine receptor I was referring to in my earlier post. It is altered in addicts (decreased expression), and genetic mutations of this receptor have been linked to several different kinds of addiction (many different drugs and obesity as well).
It should be noted that in the first study, their obese subjects didn't have initial decreased expression when compared to non-obese controls...which is a confound. So perhaps their baseline was higher, and then post-surgery, their expression went even higher? It isn't clear from reading the manuscript. Regardless, at least people are studying it in humans and in WLS patients. Oh, and the second study says they have VSG patients. Yeah, they only had 1. So, while that's better than zero...that study was still mostly RNY patients.
Obes Surg. 2010 Mar;20(3):369-74. Epub 2009 Oct 29.
Alterations of central dopamine receptors before and after gastric
bypass surgery.
Steele KE, Prokopowicz GP, Schweitzer MA, Magunsuon TH, Lidor AO,
Kuwabawa H, Kumar A, Brasic J, Wong DF.
Department of Surgery, The Johns Hopkins University School of
Medicine, Baltimore, MD 21224, USA. [email protected]
Abstract
BACKGROUND: While bariatric surgery has proved highly successful at
producing sustained weight loss, variability in treatment response
persists. A better understanding of the pathophysiology of appetite
and obesity may improve patient selection and management. Research
into feeding behavior and satiety has focused on the role of dopamine
in reward-based behaviors. Specifically, positron-emission computed
tomography (PET) has demonstrated reduced brain dopamine receptor
availability in obese subjects compared to controls. This may be due
to a primary deficiency in dopamine receptors or to secondary dopamine
receptor downregulation. We performed a preliminary study to
investigate dopamine D2 receptor activity in obese subjects before and
after laparoscopic Roux-en Y gastric bypass (LGBP).
METHODS: Five female subjects, ages 20 to 38 years old with a mean
body mass index of 45, underwent PET with [C-11] raclopride injection.
Five regions of interest were studied: ventral striatum, anterior and
posterior putamen, and anterior and posterior caudate nucleus. Repeat
PET was performed at 6 weeks following LGBP. D2 receptor binding was
compared within subjects pre- and post-surgery. Baseline D2 binding
was also compared to historical nonobese controls.
RESULTS: D2 receptor availability increased 6 weeks after gastric
bypass surgery. The increase in receptor availability appeared roughly
proportional to the amount of weight lost. No significant difference
in D2 binding was seen between the obese subjects and historical
nonobese controls.
CONCLUSIONS: Brain available dopamine D2 binding appears to increase
following GBP. This preliminary finding needs to be replicated in a
larger population but suggests that diminished D2 binding in the obese
may be due to D2 receptor downregulation. Changes in available
dopamine receptor binding may play an important role in centrally
mediated appetite suppression and resultant weight loss after LGBP.
Brain Res. 2010 Sep 2;1350:123-30. Epub 2010 Mar 31.
Decreased dopamine type 2 receptor availability after bariatric
surgery: preliminary findings.
Dunn JP, Cowan RL, Volkow ND, Feurer ID, Li R, Williams DB, Kessler
RM, Abumrad NN.
Department of Medicine, Vanderbilt University School of Medicine,
Nashville, TN 37232, USA. [email protected]
Abstract
BACKGROUND: Diminished dopaminergic neurotransmission contributes to
decreased reward and negative eating behaviors in obesity. Bariatric
surgery is the most effective therapy for obesity and rapidly reduces
hunger and improves satiety through unknown mechanisms. We
hypothesized that dopaminergic neurotransmission would be enhanced
after Roux-en-Y-Gastric Bypass (RYGB) and Vertical Sleeve Gastrectomy
(VSG) surgery and that these changes would influence eating behaviors
and contribute to the positive outcomes from bariatric surgery.
METHODS: Five females with obesity were studied preoperatively and at
approximately 7 weeks after RYGB or VSG surgery. Subjects underwent
positron emission tomography (PET) imaging with a dopamine type 2 (DA
D2) receptor radioligand whose binding is sensitive to competition
with endogenous dopamine. Regions of interest (ROI) relevant to eating
behaviors were delineated. Fasting enteroendocrine hormones were
quantified at each time point.
RESULTS: Body weight decreased as expected after surgery. DA D2
receptor availability decreased after surgery. Regional decreases
(mean+/-SEM) were caudate 10+/-3%, putamen 9+/-4%, ventral striatum
8+/-4%, hypothalamus 9+/-3%, substantia nigra 10+/-2%, medial thalamus
8+/-2%, and amygdala 9+/-3%. These were accompanied by significant
decreases in plasma insulin (62%) and leptin (41%).
CONCLUSION: The decreases in DA D2 receptor availability after RYGB
and VSG most likely reflect increases in extracellular dopamine
levels. Enhanced dopaminergic neurotransmission may contribute to
improved eating behavior (e.g. reduced hunger and improved satiety)
following these bariatric procedures.
I found 2 recent studies, but the results contradict each other, most likely due to small sample sizes. and that's half of the battle of research for you. :) This is the particular dopamine receptor I was referring to in my earlier post. It is altered in addicts (decreased expression), and genetic mutations of this receptor have been linked to several different kinds of addiction (many different drugs and obesity as well).
It should be noted that in the first study, their obese subjects didn't have initial decreased expression when compared to non-obese controls...which is a confound. So perhaps their baseline was higher, and then post-surgery, their expression went even higher? It isn't clear from reading the manuscript. Regardless, at least people are studying it in humans and in WLS patients. Oh, and the second study says they have VSG patients. Yeah, they only had 1. So, while that's better than zero...that study was still mostly RNY patients.
Obes Surg. 2010 Mar;20(3):369-74. Epub 2009 Oct 29.
Alterations of central dopamine receptors before and after gastric
bypass surgery.
Steele KE, Prokopowicz GP, Schweitzer MA, Magunsuon TH, Lidor AO,
Kuwabawa H, Kumar A, Brasic J, Wong DF.
Department of Surgery, The Johns Hopkins University School of
Medicine, Baltimore, MD 21224, USA. [email protected]
Abstract
BACKGROUND: While bariatric surgery has proved highly successful at
producing sustained weight loss, variability in treatment response
persists. A better understanding of the pathophysiology of appetite
and obesity may improve patient selection and management. Research
into feeding behavior and satiety has focused on the role of dopamine
in reward-based behaviors. Specifically, positron-emission computed
tomography (PET) has demonstrated reduced brain dopamine receptor
availability in obese subjects compared to controls. This may be due
to a primary deficiency in dopamine receptors or to secondary dopamine
receptor downregulation. We performed a preliminary study to
investigate dopamine D2 receptor activity in obese subjects before and
after laparoscopic Roux-en Y gastric bypass (LGBP).
METHODS: Five female subjects, ages 20 to 38 years old with a mean
body mass index of 45, underwent PET with [C-11] raclopride injection.
Five regions of interest were studied: ventral striatum, anterior and
posterior putamen, and anterior and posterior caudate nucleus. Repeat
PET was performed at 6 weeks following LGBP. D2 receptor binding was
compared within subjects pre- and post-surgery. Baseline D2 binding
was also compared to historical nonobese controls.
RESULTS: D2 receptor availability increased 6 weeks after gastric
bypass surgery. The increase in receptor availability appeared roughly
proportional to the amount of weight lost. No significant difference
in D2 binding was seen between the obese subjects and historical
nonobese controls.
CONCLUSIONS: Brain available dopamine D2 binding appears to increase
following GBP. This preliminary finding needs to be replicated in a
larger population but suggests that diminished D2 binding in the obese
may be due to D2 receptor downregulation. Changes in available
dopamine receptor binding may play an important role in centrally
mediated appetite suppression and resultant weight loss after LGBP.
Brain Res. 2010 Sep 2;1350:123-30. Epub 2010 Mar 31.
Decreased dopamine type 2 receptor availability after bariatric
surgery: preliminary findings.
Dunn JP, Cowan RL, Volkow ND, Feurer ID, Li R, Williams DB, Kessler
RM, Abumrad NN.
Department of Medicine, Vanderbilt University School of Medicine,
Nashville, TN 37232, USA. [email protected]
Abstract
BACKGROUND: Diminished dopaminergic neurotransmission contributes to
decreased reward and negative eating behaviors in obesity. Bariatric
surgery is the most effective therapy for obesity and rapidly reduces
hunger and improves satiety through unknown mechanisms. We
hypothesized that dopaminergic neurotransmission would be enhanced
after Roux-en-Y-Gastric Bypass (RYGB) and Vertical Sleeve Gastrectomy
(VSG) surgery and that these changes would influence eating behaviors
and contribute to the positive outcomes from bariatric surgery.
METHODS: Five females with obesity were studied preoperatively and at
approximately 7 weeks after RYGB or VSG surgery. Subjects underwent
positron emission tomography (PET) imaging with a dopamine type 2 (DA
D2) receptor radioligand whose binding is sensitive to competition
with endogenous dopamine. Regions of interest (ROI) relevant to eating
behaviors were delineated. Fasting enteroendocrine hormones were
quantified at each time point.
RESULTS: Body weight decreased as expected after surgery. DA D2
receptor availability decreased after surgery. Regional decreases
(mean+/-SEM) were caudate 10+/-3%, putamen 9+/-4%, ventral striatum
8+/-4%, hypothalamus 9+/-3%, substantia nigra 10+/-2%, medial thalamus
8+/-2%, and amygdala 9+/-3%. These were accompanied by significant
decreases in plasma insulin (62%) and leptin (41%).
CONCLUSION: The decreases in DA D2 receptor availability after RYGB
and VSG most likely reflect increases in extracellular dopamine
levels. Enhanced dopaminergic neurotransmission may contribute to
improved eating behavior (e.g. reduced hunger and improved satiety)
following these bariatric procedures.
HW: 280; SW: 255; GW1: 150; CW: 155.
