PACAP causes PAC1/VPAC2 receptor mediated hypertension and sympathoexcitation in normal and hypertensive rats.

Am J Physiol Heart Circ Physiol. 2012 Oct 1;303(7):H910-7. 
Farnham MM, Lung MS, Tallapragada VJ, Pilowsky PM.

"Pituitary adenylate cyclase-activating polypeptide (PACAP) is an excitatory neuropeptide that plays and important role in hypertension and stress responses". 

The authors proposed an idea that PACAP acts as a sympathoexcitatory agent in the RVLM of normotensive and hypertensive rats. The had 3 specific aims for the experiment and tested them using different mechanisms as in described in the above illustration. The major findings of this study is that injection of PACAP in the RVLM caused an increase in splanchnic SNA, heart rate and MAP in SHR, WKY and SD rats. Pretreatment with PAC1/VPAC2 receptor antagonist PACAP (6-38) attenuated this response but did not produce any changes when injected alone suggesting that PACAP receptors are not tonically active. PACAP (6-38)  in the RVLM produced no changes in sSNA or MAP in the SHR suggesting they may not play a role in maintaining hypertension in SHR.

-Madhan