Editing Chemoreceptor trigger zone (section)

===Phosphodiesterases===

Recent studies have found that [[phosphodiesterase]] 4 (PDE4) inhibitors, such as [[Rolipram]], cause emesis as one of their side effects.<ref name="Mori">{{cite journal|last1=Mori|first1=F|last2=Pérez-Torres|first2=S|last3=De Caro|first3=R|last4=Porzionato|first4=A|last5=Macchi|first5=V|last6=Beleta|first6=J|last7=Gavaldà|first7=A|last8=Palacios|first8=JM|last9=Mengod|first9=G|title=The human area postrema and other nuclei related to the emetic reflex express cAMP phosphodiesterases 4B and 4D|journal=Journal of Chemical Neuroanatomy|date=September 2010|volume=40|issue=1|pages=36–42|doi=10.1016/j.jchemneu.2010.03.004|pmid=20347962|hdl=10261/147758|s2cid=43192630|hdl-access=free}}</ref> It has been found that these PDE4 isoforms are expressed in the CTZ and in the brainstem in general.<ref name="Mori"/> The [[mRNA]] products from genes that code for these PDE4 isoforms are plentiful in the CTZ, and not only located in CTZ [[neurons]], but also in [[glial cells]] and blood vessels associated with the CTZ neurons.<ref name="Mori"/> PDE4 mRNAs are transcribed more in the area postrema and the CTZ than anywhere else in the brainstem.<ref name="Mori"/> The PDE4 degrades the phosphodiester bonds in the [[second messenger]] molecule [[cyclic adenosine monophosphate]] (cAMP), which is one of the ways the brain relays information. By modifying cAMP signaling in the CTZ, it is thought that this could mediate the emetic effects of PDE4 inhibitors in the CTZ.<ref name="Mori"/>