Gender Difference in the Role of Posterodorsal Amygdala on the Regulation of Food Intake, Adiposity and Immunological Responses in Albino Wistar Rats

Abstract

Lesion of posterodorsal amygdala (PDA) has been known to produce hyperphagia and obesity in animal models. However, the influence of gender on food intake (FI), body weight (BW) and immunological parameters following PDA lesion is not yet known. The present work was carried out to study the effect of gender on the regulation of FI, BW and immunological parameters following lesions of PDA in albino Wistar rats. Twenty-four albino Wistar rats were divided equally into 2 groups - PDA group and control group - with 6 male and 6 female rats in each. In the experimental group, bilateral electrolytic lesion of the respective nuclei was performed by stereotaxy and post-lesion parameters were recorded. In the control group, sham lesion was made. Male-female difference in each parameter was determined. Following PDA lesion, FI increased significantly in both male (p < 0.001) and female rats (p < 0.01) but the percentage increase in FI was significantly more in female rats (p < 0.001). BW also increased in both the sexes but the increase in BW was significant only in male rats (p < 0.05). Both male and female rats showed increase in the concentration of cluster of differentiation 4 (CD4), but the significant increase in CD4 concentration (p < 0.01) was seen only in male rats. CD8 concentration increased significantly in male rats (p < 0.05). The liver weight-BW ratio was significantly greater in female rats (p < 0.001) following PDA lesions. Lesion of PDA results in accentuation of FI and BW gain and activation of immunity. There is a gender difference in the inhibitory control of PDA on FI, BW and immunity.

Sex Commonalities and Differences in Obesity‐Related Alterations in Intrinsic Brain Activity and Connectivity

“…Activation of the inferior frontal cortices is associated with top-down control and inhibition processes involved in the self-regulation of food cravings and impulses associated with hedonic ingestion ( 37 ). A negative association between frontal cortical-basal ganglia functional connectivity has been linked to reduced hunger control ( 9 , 10 ), increased weight gain ( 14 ) and appetite ( 6 , 8 ) in obesity. When viewed together, our results may explain why the modulation of impulse control is more associated with increased hedonic ingestion and obesity in women than in men.…”

“…Although women have an increased propensity to gain total body fat, especially subcutaneous abdominal fat when compared to men, men tend to have more visceral adipose tissue, which has been associated with increased metabolic and cardiovascular disease ( 5 ). Sex differences in eating behaviors have also been identified in both rodent and human experiments ( 6 ). Food cravings, whether cue-induced, trait-related, or state-related, can lead to increased hedonic eating behaviors, which has also been associated with increased risk of obesity ( 7 ).…”

History of early life adversity is associated with increased food addiction and sex‐specific alterations in reward network connectivity in obesity

“…Although studies in the USA suggest similar rates of obesity in men and women , international studies show a greater prevalence in women . Furthermore, striking sex differences have been observed in eating behaviours and food cravings, resulting in an increased risk for obesity . For example, women with obesity report higher food addiction behaviours, cravings, comorbidity and reward sensitivity than men with obesity .…”

Altered Functional Connectivity of the Amygdala and Sex Differences in Functional Dyspepsia

“…This may be the reason why the CMA and BLA, but not the SFA, showed significantly abnormal rsFC with the fronto-temporo-insular cortical areas in patients with FD compared with HS in this study. Furthermore, many studies have demonstrated that the BLA and CMA serve as the main amygdala subregions involved in processing food intake and visceral sensation (21,22,38,39). Thus, the altered BLA and CMA rsFC in this study may suggest abnormal visceral sensory input and output connections of the amygdala in FD.…”

“…in patients with FD (13–19). Among these altered brain regions, the amygdala is believed to be one of the key regions in the central pathogenesis of FD (15–17,20) because of its wide involvement in processing interoceptive signals of fullness and satiety (21), food intake (22), endogenous pain inhibition (23), and emotion expression and regulation (24,25). In addition, the role of the amygdala in sex-related difference in cerebral activity has also been identified in brain imaging studies performed on healthy subjects (HS) (23,32,33), patients with irritable bowel syndrome (IBS) (30,31), and patients with chronic visceral pain (23).…”