AIM:To determine the effect of pituitary adenylate cy-clase-activating polypeptide (PACAP) on left gastric artery (LGA) flow and to unveil the structural or functional important sites that may be critical for discrimi...AIM:To determine the effect of pituitary adenylate cy-clase-activating polypeptide (PACAP) on left gastric artery (LGA) flow and to unveil the structural or functional important sites that may be critical for discrimination of different receptor subtypes. METHODS: Peptides, including PACAP-27, PACAP-38, amino acid substituted PACAP-27 and C-terminus truncated analogues PACAP (27-38), were synthesized by a simultaneous multiple solid-phase peptide synthesizer. Flow probes of an ultrasound transit-time blood flowmeter were placed around the LGA of beagle dogs. Whenpeptides were infused intravenously, the blood flow was measured.RESULTS: [Ala4, Val5]-PACAP-27 caused a concentration-dependent vasodepressor action which was similar to that caused by PACAP-27. The LGA blood flow response to [Ala4, Val5]-PACAP-27 was significantly higher than that to PACAP-27, which was similar to that to vasoactive intestinal polypeptide (VIP) at the same dose. [Ala6]-PACAP-27 did not increase the peak LGA ? ow. [Gly8]-PACAP-27 showed a similar activity to VIP. [Asn24, Ser25, Ile26]-PACAP-27 did not change the activity of peptides at all doses. CONCLUSION: NH2 terminus is more important to biological activity of peptides and specifi c receptor recognition than COOH-terminus.展开更多
Pituitary adenylate cyclase-activating polypeptide（PACAP） is an endogenous peptide with neuroprotective effects on retinal neurons, but the precise mechanism underlying these effects remains unknown. Considering the...Pituitary adenylate cyclase-activating polypeptide（PACAP） is an endogenous peptide with neuroprotective effects on retinal neurons, but the precise mechanism underlying these effects remains unknown. Considering the abundance of mitochondria in retinal ganglion cells（RGCs）, we postulate that the protective effect of PACAP is associated with the regulation of mitochondrial function. RGC-5 cells were subjected to serum deprivation for 48 hours to induce apoptosis in the presence or absence of 100 nM PACAP. As revealed with the Cell Counting Kit-8 assay, PACAP at different concentrations significantly increased the viability of RGC-5 cells. PACAP also inhibited the excessive generation of reactive oxygen species in RGC-5 cells subjected to serum deprivation. We also showed by flow cytometry that PACAP inhibited serum deprivation-induced apoptosis in RGC-5 cells. The proportions of apoptotic cells and cells with mitochondria depolarization were significantly decreased with PACAP treatment. Western blot assays demonstrated that PACAP increased the levels of Bcl-2 and inhibited the compensatory increase of PAC1. Together, these data indicate protective effects of PACAP against serum deprivation-induced apoptosis in RGCs, and that the mechanism of this action is associated with maintaining mitochondrial function.展开更多
基金Supported by (in part) Grants from Ministry of Education,Culture,Science,and Technology,Japan Society for the Promotion of Science and Special Fund of Six-Talented Peak of Jiangsu Province,No.07-B-15 (IB07)
文摘AIM:To determine the effect of pituitary adenylate cy-clase-activating polypeptide (PACAP) on left gastric artery (LGA) flow and to unveil the structural or functional important sites that may be critical for discrimination of different receptor subtypes. METHODS: Peptides, including PACAP-27, PACAP-38, amino acid substituted PACAP-27 and C-terminus truncated analogues PACAP (27-38), were synthesized by a simultaneous multiple solid-phase peptide synthesizer. Flow probes of an ultrasound transit-time blood flowmeter were placed around the LGA of beagle dogs. Whenpeptides were infused intravenously, the blood flow was measured.RESULTS: [Ala4, Val5]-PACAP-27 caused a concentration-dependent vasodepressor action which was similar to that caused by PACAP-27. The LGA blood flow response to [Ala4, Val5]-PACAP-27 was significantly higher than that to PACAP-27, which was similar to that to vasoactive intestinal polypeptide (VIP) at the same dose. [Ala6]-PACAP-27 did not increase the peak LGA ? ow. [Gly8]-PACAP-27 showed a similar activity to VIP. [Asn24, Ser25, Ile26]-PACAP-27 did not change the activity of peptides at all doses. CONCLUSION: NH2 terminus is more important to biological activity of peptides and specifi c receptor recognition than COOH-terminus.
基金supported by grants from the Medical Scientific Research Foundation of Guangdong Province of China,No.A2016271the Natural Science Foundation of Guangdong Province of China,No.2016A030313208the Science and Technology Planning Project of Guangdong Province of China,No.2014A020212393
文摘Pituitary adenylate cyclase-activating polypeptide（PACAP） is an endogenous peptide with neuroprotective effects on retinal neurons, but the precise mechanism underlying these effects remains unknown. Considering the abundance of mitochondria in retinal ganglion cells（RGCs）, we postulate that the protective effect of PACAP is associated with the regulation of mitochondrial function. RGC-5 cells were subjected to serum deprivation for 48 hours to induce apoptosis in the presence or absence of 100 nM PACAP. As revealed with the Cell Counting Kit-8 assay, PACAP at different concentrations significantly increased the viability of RGC-5 cells. PACAP also inhibited the excessive generation of reactive oxygen species in RGC-5 cells subjected to serum deprivation. We also showed by flow cytometry that PACAP inhibited serum deprivation-induced apoptosis in RGC-5 cells. The proportions of apoptotic cells and cells with mitochondria depolarization were significantly decreased with PACAP treatment. Western blot assays demonstrated that PACAP increased the levels of Bcl-2 and inhibited the compensatory increase of PAC1. Together, these data indicate protective effects of PACAP against serum deprivation-induced apoptosis in RGCs, and that the mechanism of this action is associated with maintaining mitochondrial function.
