Does glutamatergic receptor modulation in the vlPAG affect cardiovascular activity in normotensive and hypovolemic hemorrhagic rats?
Glutamate in the vlPAG increases cardiovascular parameters primarily via NMDA receptors, but its overall cardiovascular role in normal and hemorrhagic conditions appears limited.
OBJECTIVES: Periaqueductal gray (PAG) is a mesencephalic area divided into four columns including ventrolateral periaqueductal gray (vlPAG). vlPAG plays a role in cardiovascular regulation during normal and hemorrhagic (Hem) conditions. Due to presence of glutamate in this area, we evaluated the effect of glutamatergic receptors of this area on cardiovascular activity in normotensive and hypovolemic Hem rats. MATERIALS AND METHODS: Animals were divided into twelve groups: saline (vehicle), Glutamate, GYK52466 (non-NMDA receptor antagonist), and MK801 (NMDA receptor antagonist) with and without Glu microinjected into vlPAG in normal and Hem conditions. Following the femoral artery cannulating and microinjecting, changes (Δ) of heart rate (HR), systolic blood pressure (SBP), and mean arterial pressure (MAP) were recorded via a PowerLab unit. RESULTS: >0.05). CONCLUSION: The glutamatergic system of vlPAG increases cardiovascular values that are mostly mediated through the NMDA receptor. Since vlPAG is well known as an inhibitory region, it seems that glutamate does not have a noteworthy cardiovascular role in vlPAG during Hem and normal conditions.
Alikhani et al. (Sat,) studied this question.