h-89 and Infarction--Middle-Cerebral-Artery

We aim to investigate the effects of sevoflurane on the ATPase activity of the hippocampal neurons in rats with cerebral ischemia-reperfusion injury (IRI) via the cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) signaling pathway. Sixty rats were assigned into the normal, model and sevoflurane groups (n = 20, the latter two groups were established as focal cerebral IRI models). The ATPase activity was detected using an ultramicro Na (+)-K (+)-ATP enzyme kit. Immunohistochemical staining was used to detect the positive protein expression of cAMP and PKA. The hippocampal neurons were assigned to the normal, IRI, IRI + sevoflurane, IRI + forskolin, IRI + H89 and IRI + sevoflurane + H89 groups. qRT-PCR and Western blotting were performed for the expressions of cAMP, PKA, cAMP-responsive element-binding protein (CREB) and brain derived neurotrophic factor (BDNF). The normal and sevoflurane groups exhibited a greater positive protein expression of cAMP and PKA than the model group. Compared with the normal group, the expressions of cAMP, PKA, CREB and BDNF all reduced in the IRI, model and IRI + H89 groups. The sevoflurane group showed higher cAMP, PKA, CREB and BDNF expressions than the model group. Compared with the IRI group, ATPase activity and expressions of cAMP, PKA, CREB and BDNF all increased in the normal, IRI + sevoflurane and IRI + forskolin groups but decreased in the IRI + H89 group. It suggests that sevoflurane could enhance ATPase activity in hippocampal neurons of cerebral IRI rats through activating cAMP-PKA signaling pathway.

Topics: Animals; Brain-Derived Neurotrophic Factor; Colforsin; CREB-Binding Protein; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Disease Models, Animal; Gene Expression Regulation; Germ-Free Life; Hippocampus; Humans; Infarction, Middle Cerebral Artery; Isoquinolines; Male; Neurons; Neuroprotective Agents; Platelet Aggregation Inhibitors; Protein Kinase Inhibitors; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Sevoflurane; Sodium-Potassium-Exchanging ATPase; Sulfonamides

The cyclic AMP-dependent protein kinase (PKA), which activates prosurvival signaling proteins, has been implicated in the expression of long-term potentiation and hippocampal long-term memory. It has come to light that H89 commonly known as the PKA inhibitor have diverse roles in the nervous system that are unrelated to its role as a PKA inhibitor. We have investigated the role of H89 in ischemic and reperfusion injury. First, we examined the expression of postsynaptic density protein 95 (PSD95), microtubule-associated protein 2 (MAP2), and synaptophysin in mouse brain after middle cerebral artery occlusion injury. Next, we examined the role of H89 pretreatment on the expression of brain-derived neurotrophic factor (BDNF), PSD95, MAP2, and the apoptosis regulators Bcl2 and cleaved caspase-3 in cultured neuroblastoma cells exposed to hypoxia and reperfusion injury. In addition, we investigated the alteration of AKT activation in H89 pretreated neuroblastoma cells under hypoxia and reperfusion injury. The data suggest that H89 may contribute to brain recovery after ischemic stroke by regulating neuronal death and proteins related to synaptic plasticity.

Topics: Animals; Apoptosis Regulatory Proteins; Brain Ischemia; Brain-Derived Neurotrophic Factor; Cell Death; Cyclic AMP-Dependent Protein Kinases; Disks Large Homolog 4 Protein; Guanylate Kinases; Hypoxia, Brain; Infarction, Middle Cerebral Artery; Isoquinolines; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Microtubule-Associated Proteins; Neurons; Protein Kinase Inhibitors; Reperfusion Injury; Sulfonamides; Synapses