µ-opioid receptors in the central nucleus of the amygdala modulate sucrose solution intake in rats / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the role of µ-opioid receptors (MOR) in the central nucleus of the amygdala (CeA) in modulating sucrose solution intake in rats.</p><p><b>METHODS</b>Sprague-Dawley rats received intra-CeA injection of MOR agonist DAMGO or saline, and then underwent two bottle choice test between sucrose solution and distilled water. After intake of sucrose solution or distilled water, activated neurons in the CeA were labeled and identified with MOR/Fos-double labeling immunohistochemistry.</p><p><b>RESULTS</b>Compared with saline injection, intra-CeA injection of DAMGO significantly increased sucrose solution intake in rats over a 3-h period. Sucrose solution intake induced significantly more c-Fos and MOR/Fos double-labeled neurons in the CeA than distilled water intake.</p><p><b>CONCLUSIONS</b>The CeA participates in modulation of sucrose intake in rats, and MOR may partly mediate this mechanism.</p>

Microinjection of NMDA-type glutamate receptor agonist NMDA and antagonist D-AP-5 into the central nucleus of the amygdale alters water intake rather than food intake / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the role of N-Methyl-D-aspartic acid (NMDA)-type glutamate receptors in the central nucleus of the amygdale (CeA) in food and water intake.</p><p><b>METHODS</b>Male Sprague-Dawley rats with stainless steel cannulae implanted unilaterally into the CeA were used. The prototypic NMDA receptor agonist NMDA, or the selective NMDA receptor antagonist D(-)-2-amino-5-phosphonopentanoic acid (D-AP-5) was microinjected into the CeA of satiated and euhydrated rats.</p><p><b>RESULTS</b>Intra-CeA injection of 8.50, 17.00, or 34.00 nmol NMDA did not alter food intake but significantly increased water intake 0-1 h after the injection (F(3,32)=3.191, P=0.037) independent of food intake. Without affecting the food intake, injection of 6.34, 12.70, or 25.40 nmol D-AP-5 into the CeA significantly decreased water intake 0-1 h after the injection (F(3,28)=3.118, P=0.042) independent of food intake.</p><p><b>CONCLUSION</b>NMDA receptors in the CeA may participate in the control of water intake rather than food intake.</p>