Moreover, an obvious stimulatory response to AJEA was observed only in the DCLM, but not in the other regions of GI smooth muscles including the distal colon circular muscles.
Interestingly, AJEA gradually increased the low frequency contraction with high amplitude in the DCLM of rats, and a maximal contraction of DCLM was observed at around 70 min after treating AJEA.
2] receptor-preferring antagonist, methoctramine, abolished only the later phase of contractile response of DCLM to AJEA (Fig.
These cellular events lead us to suppose that activation of serotoninergic receptors also possibly mediates the stimulatory effects of AJEA on the DCLM contractility through enhancing ACh releases.
So, we have considered that in addition to the muscarinic receptors, the de novo cellular pathway possibly mediates the stimulatory effect of AJEA on the spontaneous contractility of DCLM in rats and made a hypothesis as following: AJEA activates the ChAT and TPH activity at presynaptic enteric nerves, and their activation can stimulate the ACh release at the myenteric neurons and nerve terminals, results in producing the DCLM contractions.