This is a study looking at biochemical markers of stress in rats using a very common acupuncture point Pericardium 6. (Pericardium 6 is the point often used for motion sickness or nausea in pregnancy.)
They gave the animals mild stressors for 8 weeks and compared acupuncture at Pericardium 6 to Triple Heater 5 (another common point on the other side of the arm.)
Their conclusion was
“The present results demonstrated that acupuncture was effective in restoring CMS-related biochemical and behavioral impairments such as anxiety and anhedonia and that acupuncture point was more effective than non-acupuncture point. These results suggest that acupuncture has a therapeutic effect on chronic stress-related diseases such as depression and anxiety.
The effects of acupuncture stimulation at PC6 (Neiguan) on chronic mild stress-induced biochemical and behavioral responses.”
Neurosci Lett. 2009 May 7.
Division of Brain Disease, Center for Biomedical Science, National Institute of Health, Seoul, 122-701 Republic of Korea.

Kim H, Park HJ, Han SM, Hahm DH, Lee HJ, Kim KS, Shim I.