Effects of inducible nitric oxide synthase blockade within the periaqueductal gray on cardiovascular responses during mechanical, heat, and cold nociception.

We have examined the role of inducible nitric oxide synthase (iNOS) within the dorsolateral periaqueductal gray mater (dlPAG) on cardiovascular responses during mechanical, thermal, and cold nociception in anesthetized rats. Mechanical stimulus was applied by a unilateral hindpaw pinch for 10 s that increased mean arterial pressure (MAP) and heart rate (HR). Bilateral microdialysis of a selective iNOS inhibitor, aminoguanidine (AGN; 10 μM), into the dlPAG for 30 min augmented MAP and HR responses during a mechanical stimulation.

Effects of endothelial NOS antagonism within the periaqueductal gray on cardiovascular responses and neurotransmission during mechanical, heat, and cold nociception.

Nitric oxide (NO) is synthesized from L-arginine using NO synthase (NOS) enzyme that exists as 3 isoforms: endothelial (eNOS), neuronal (nNOS), and inducible (iNOS). We examined the role of eNOS within the dorsolateral periaqueductal gray mater (dlPAG) on cardiovascular responses along with glutamate and GABA concentrations during mechanical-, heat-, and cold-induced nociception in anesthetized rats. Mechanical stimulus was applied by a 10-second hindpaw pinch that increased mean arterial pressure (MAP) and heart rate (HR).

Modulation of cardiovascular responses and neurotransmission during peripheral nociception following nNOS antagonism within the periaqueductal gray.

Nitric oxide (NO) within the dorsal periaqueductal gray matter (dPAG) attenuated cardiovascular responses and changes in the concentrations of glutamate during both mechanical and thermal nociceptive stimulation [Ishide, T., Amer, A., Maher, T.

Medullary monoamines and NMDA-receptor regulation of cardiovascular responses during peripheral nociceptive stimuli.

We have previously reported that AMPA-receptor blockade within the rostral ventrolateral medulla (RVLM) attenuates cardiovascular responses and extracellular concentrations of glutamate during mechanical, but not during thermal stimulation [Gray, T., Lewis III, E., Maher, T.