In this study, we used a rat model of pulmonary arterial hypertension (PAH) induced by monocrotaline (MCT) to investigate the role and mechanism of angiotensin (Ang)-(1-7) in regulating pulmonary artery diastolic function. Three weeks after subcutaneous injection of MCT or normal saline, the right ventricular systolic pressure (RVSP) and right ventricular hypertrophy index (RVHI) of rats were detected using a right heart catheter. Vascular endothelium-dependent relaxation was evaluated by acetylcholine (ACh)-induced vasodilation. The relaxation function of vascular smooth muscle was evaluated by sodium nitroprusside (SNP)-induced vasodilation. Human pulmonary artery endothelial cells (HPAECs) were incubated with Ang-(1-7) to measure nitric oxide (NO) release levels. The results showed that compared with control rats, RVSP and RVHI were significantly increased in the MCT-PAH rats, and both ACh or SNP-induced vasodilation were worsened. Incubation of pulmonary artery of MCT-PAH rats with Ang-(1-7) (1 × 10^-9-1 × 10^-4 mol/L) caused significant vaso-relaxation. Pre-incubation of Ang-(1-7) in the pulmonary artery of MCT-PAH rats significantly improved ACh-induced endothelium-dependent relaxation, but had no significant effect on SNP-induced endothelium-independent relaxation. In addition, Ang-(1-7) treatment significantly increased NO levels in HPAECs. The Mas receptor antagonist A-779 inhibited the effects of Ang-(1-7) on endothelium-dependent relaxation and NO release from endothelial cells. The above results demonstrate that Ang-(1-7) promotes the release of NO from endothelial cells by activating Mas receptor, thereby improving the endothelium-dependent relaxation function of PAH pulmonary arteries.
Rats ; Humans ; Animals ; Vasodilation ; Pulmonary Arterial Hypertension ; Monocrotaline/toxicity* ; Rats, Sprague-Dawley ; Hypertension, Pulmonary/chemically induced* ; Endothelial Cells ; Pulmonary Artery ; Endothelium ; Acetylcholine/pharmacology* ; Nitroprusside/pharmacology*

Acetylcholine (ACh) is an important neuromodulator in various cognitive functions. However, it is unclear how ACh influences neural circuit dynamics by altering cellular properties. Here, we investigated how ACh influences reverberatory activity in cultured neuronal networks. We found that ACh suppressed the occurrence of evoked reverberation at low to moderate doses, but to a much lesser extent at high doses. Moreover, high doses of ACh caused a longer duration of evoked reverberation, and a higher occurrence of spontaneous activity. With whole-cell recording from single neurons, we found that ACh inhibited excitatory postsynaptic currents (EPSCs) while elevating neuronal firing in a dose-dependent manner. Furthermore, all ACh-induced cellular and network changes were blocked by muscarinic, but not nicotinic receptor antagonists. With computational modeling, we found that simulated changes in EPSCs and the excitability of single cells mimicking the effects of ACh indeed modulated the evoked network reverberation similar to experimental observations. Thus, ACh modulates network dynamics in a biphasic fashion, probably by inhibiting excitatory synaptic transmission and facilitating neuronal excitability through muscarinic signaling pathways.
Cholinergic Agents/pharmacology* ; Acetylcholine/metabolism* ; Neurons/metabolism* ; Synaptic Transmission/physiology*

Cardiovascular diseases are life-threatening illnesses with high morbidity and mortality. Suppressed vagal (parasympathetic) activity and increased sympathetic activity are involved in these diseases. Currently, pharmacological interventions primarily aim to inhibit over-excitation of sympathetic nerves, while vagal modulation has been largely neglected. Many studies have demonstrated that increased vagal activity reduces cardiovascular risk factors in both animal models and human patients. Therefore, the improvement of vagal activity may be an alternate approach for the treatment of cardiovascular diseases. However, drugs used for vagus nerve activation in cardiovascular diseases are limited in the clinic. In this review, we provide an overview of the potential drug targets for modulating vagal nerve activation, including muscarinic, and β-adrenergic receptors. In addition, vagomimetic drugs (such as choline, acetylcholine, and pyridostigmine) and the mechanism underlying their cardiovascular protective effects are also discussed.
Acetylcholine ; pharmacology ; Animals ; Cardiovascular Diseases ; drug therapy ; Cholinergic Agents ; therapeutic use ; Humans ; Receptors, Muscarinic ; drug effects ; Sympathetic Nervous System ; drug effects ; physiopathology ; Vagus Nerve ; drug effects ; physiopathology

OBJECTIVE: To investigate the effects of Xiaotan Huayu Liqiao formula (the Chinese Medicine) on mesenteric artery function in rats exposed to chronic intermittent hypoxia (CIH), and to explore the related mechanism. METHODS: Forty-eight male SD rats were randomly divided into four groups as Normoxia, CIH, Formula+CIH and formula group. Rats were exposed to normoxia in the Normoxia and Formula group, or intermittent hypoxia in CIH or Formula+CIH group. Xiaotan Huayu Liqiao formula was given at 24g/kg by intragastric administration before intermittent hypoxia exposure. The pathological changes of mesenteric artery were determined by HE staining, and the relaxation of mesenteric artery (induced by acetylcholine(ACh) and L-arginine(L-Arg)) was recorded by microvascular ring technique. Serums of all rats were collected (0 d and 21 d) and the content of NO was detected by ELISA. The levels of endothelial nitric oxide synthase (eNOS) and p-eNOS were measured by Western blot. RESULTS: Compared with Normoxia group, the mesenteric arterial endothelial injury and media thickening were observed and the relaxation of mesenteric artery was significantly reduced in rats exposed to CIH. The level of NO in serum and the ratio of p-eNOS/eNOS were also decreased in the CIH group. Xiaotan Huayu Liqiao formula administration improved the pathologic changes and dilatation function of mesenteric artery, increased the levels of NO and p-eNOS. Compared with Normoxia group,all the results were not observed significant difference in Formula group. CONCLUSION Xiaotan Huayu Liqiao formula increased the bioavailability of NO, and ameliorated the CIH induced mesenteric artery function injury.
Acetylcholine ; Animals ; Drugs, Chinese Herbal ; pharmacology ; Hypoxia ; pathology ; Male ; Mesenteric Arteries ; drug effects ; pathology ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type III ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo examine the effect of icariin (ICA) on the cognitive impairment induced by traumatic brain injury (TBI) in mice and the underlying mechanisms related to changes in hippocampal acetylation level.

METHODSThe modifified free-fall method was used to establish the TBI mouse model. Mice with post-TBI cognitive impairment were randomly divided into 3 groups using the randomised block method (n=7): TBI (vehicle-treated), low-dose (75 mg/kg) and high-dose (150 mg/kg) of ICA groups. An additional sham-operated group (vehicle-treated) was employed. The vehicle or ICA was administrated by gavage for 28 consecutive days. The Morris water maze (MWM) test was conducted. Acetylcholine (ACh) content, mRNA and protein levels of choline acetyltransferase (ChAT), and protein levels of acetylated H3 (Ac-H3) and Ac-H4 were detected in the hippocampus.

RESULTSCompared with the sham-operated group, the MWM performance, hippocampal ACh content, mRNA and protein levels of ChAT, and protein levels of Ac-H3 and Ac-H4 were signifificantly decreased in the TBI group (P<0.05). High-dose of ICA signifificantly ameliorated the TBI-induced weak MWM performance, increased hippocampal ACh content, and mRNA and protein levels of ChAT, as well as Ac-H3 protein level compared with the TBI group (P<0.05).

CONCLUSIONICA improved post-TBI cognitive impairment in mice by enhancing hippocampal acetylation, which improved hippocampal cholinergic function and ultimately improved cognition.

Acetylation ; Acetylcholine ; metabolism ; Animals ; Brain Injuries, Traumatic ; complications ; Choline O-Acetyltransferase ; genetics ; metabolism ; Cognitive Dysfunction ; drug therapy ; etiology ; Flavonoids ; chemistry ; pharmacology ; therapeutic use ; Hippocampus ; pathology ; Histones ; metabolism ; Homeostasis ; drug effects ; Male ; Maze Learning ; drug effects ; Mice ; RNA, Messenger ; genetics ; metabolism

Berberine (BBR) is an isoquinoline alkaloid extracted from Rhizoma coptidis and has been used for treating type 2 diabetes mellitus (T2DM) in China. The development of T2DM is often associated with insulin resistance and impaired glucose uptake in peripheral tissues. In this study, we examined whether BBR attenuated glucose uptake dysfunction through the cholinergic anti-inflammatory pathway in HepG2 cells. Cellular glucose uptake, quantified by the 2-[N-(7-Nitrobenz-2-oxa-1,3-diazol-4-yl)-amino]-2-deoxy-D-glucose (2-NBDG), was inhibited by 21% after HepG2 cells were incubated with insulin (10(-6) mol/L) for 36 h. Meanwhile, the expression of alpha7 nicotinic acetylcholine receptor (α7nAChR) protein was reduced without the change of acetylcholinesterase (AChE) activity. The level of interleukin-6 (IL-6) in the culture supernatant, the ratio of phosphorylated I-kappa-B kinase-β (IKκβ) Ser181/IKKβ and the expression of nuclear factor-kappa B (NF-κB) p65 protein were also increased. However, the treatment with BBR enhanced the glucose uptake, increased the expression of α7nAChR protein and inhibited AChE activity. These changes were also accompanied with the decrease of the ratio of pIKKβ Ser181/IKKβ, NF-κB p65 expression and IL-6 level. Taken together, these results suggest that BBR could enhance glucose uptake, and relieve insulin resistance and inflammation in HepG2 cells. The mechanism may be related to the cholinergic anti-inflammatory pathway and the inhibition of AChE activity.
Berberine ; pharmacology ; Glucose ; metabolism ; Hep G2 Cells ; Humans ; Hypoglycemic Agents ; pharmacology ; I-kappa B Kinase ; metabolism ; I-kappa B Proteins ; metabolism ; Insulin ; metabolism ; Insulin Resistance ; Interleukin-6 ; metabolism ; Transcription Factor RelA ; metabolism ; alpha7 Nicotinic Acetylcholine Receptor ; genetics ; metabolism

PURPOSE: Reduced brain glucose metabolism and basal forebrain cholinergic neuron degeneration are common features of Alzheimer's disease and have been correlated with memory function. Although regions representing glucose hypometabolism in patients with Alzheimer's disease are targets of cholinergic basal forebrain neurons, the interaction between cholinergic denervation and glucose hypometabolism is still unclear. The aim of the present study was to evaluate glucose metabolism changes caused by cholinergic deficits. MATERIALS AND METHODS: We lesioned basal forebrain cholinergic neurons in rats using 192 immunoglobulin G-saporin. After 3 weeks, lesioned animals underwent water maze testing or were analyzed by 18F-2-fluoro-2-deoxyglucose positron emission tomography. RESULTS: During water maze probe testing, performance of the lesioned group decreased with respect to time spent in the target quadrant and platform zone. Cingulate cortex glucose metabolism in the lesioned group decreased, compared with the normal group. Additionally, acetylcholinesterase activity and glutamate decarboxylase 65/67 expression declined in the cingulate cortex. CONCLUSION: Our results reveal that spatial memory impairment in animals with selective basal forebrain cholinergic neuron damage is associated with a functional decline in the GABAergic and cholinergic system associated with cingulate cortex glucose hypometabolism.
Acetylcholine/metabolism ; Alzheimer Disease ; Animals ; Antibodies, Monoclonal/*pharmacology ; Basal Forebrain/*drug effects/metabolism ; Cholinergic Agents/administration & dosage/*pharmacology ; Cholinergic Neurons/*drug effects/metabolism ; Fluorodeoxyglucose F18 ; GABAergic Neurons/*drug effects/metabolism ; Glucose/*metabolism ; Gyrus Cinguli/*drug effects/metabolism ; Humans ; Injections ; Maze Learning ; Motor Activity/physiology ; Positron-Emission Tomography ; Rats ; Ribosome Inactivating Proteins, Type 1/*pharmacology

OBJECTIVETo explore targets of Chinese herbal medicine at cellular and molecular leve1s through an experimental study on Yinxingye Capsule (YC) intervening vascular endothelial cell apoptoeis of hyperhornocysteinemia (HHcy) rats.

METHODSThe HHcy model was prepared in male Wistar rats. Totally 42 rats were randomly divided into 4 groups, i.e., the control group (n =10), the model group (n = 11), the YC group (n =11), the folic acid group (n =10). Carboxy methyl cellulose (CMC) solution (1%) was administered to rats in the control group by gastrogavage.3% methionine suspension at 1. 5 g/kg was administered to rats in the model group by gastrogavage. 3% methionine suspension at 1. 5 g/kg and folic acid suspension at 0. 06 g/kg was administered to rats in the folic acid group by gastrogavage. 3% methionine suspension at 1. 5 g/kg and YC at 0. 02 g/kg was administered to rats in the YC group by gastrogavage. Morphological changes of aortic tissue were observed by hematoxylin eosin (HE) staining. The plasma homocysteine (Hcy) level was detected in each group. The endothelium-dependent diastolic functions of the thoracic aorta on different concentrations of sodium nitroprusside (SNP) and acetylcholine (Ach) were detected. Gene expressions of Bcl-2-associated X protein (BAX), inducible nitric oxide synthase (iNOS), c-Fos, cellular inhibitor of apoptosis protein 2 (c-IAP2) were detected by real time polymerase chain reaction (RT-PCR).

RESULTSPathological results showed that thickening aortic endothelium, swollen and desquamated endothelial cells. Few foam cells could be seen in the model group. Myoma-like proliferation of smooth muscle cells in tunica media could also be seen. These pathological changes were milder in the YC group and the folic acid group. Compared with the control group, plasma Hcy levels increased in the model group (P <0. 05). The endothelium-dependent diastolic rates at 10(-6) and 10(-4)mol/L Ach and 10(-7) -10(-3)mol/L SNP all decreased in the model group (P <0. 01, P <0. 05). Gene expressions of Bax, c-Fos, and iNOS increased, but c-IAP2 gene expressions decreased in the model group (all P <0. 05). Compared with the model group, plasma Hcy levels decreased in the YC group and the folic acid group (P <0. 05). The endothelium-dependent diastolic rates increased in the YC group and the folic acid group at various SNP concentrations except 10(-6) mol/L SNP in the folic acid group. The endothelium-dependent diastolic rates increased in the YC group and the folic acid group at 10(-6) and 10(-4)mol/L Ach (all P <0. 05). Gene expressions of Bax, c-Fos, and iNOS decreased in the YC group and the folic acid group, but c-IAP2 gene expression increased in the folic acid group (all P <0. 05).

CONCLUSIONYC could reduce plasma Hcy levels, down-regulate gene expressions of Bax, c-Fos, and iNOS, thereby reducing apoptosis of vascular endothelial cells, improving vascular endothelial function, and delaying atherosclerotic process.

Acetylcholine ; Animals ; Aorta ; Aorta, Thoracic ; Apoptosis ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; therapeutic use ; Endothelial Cells ; Endothelium, Vascular ; Hyperhomocysteinemia ; drug therapy ; Male ; Nitric Oxide Synthase Type II ; Nitroprusside ; Proto-Oncogene Proteins c-fos ; Rats ; Rats, Wistar ; bcl-2-Associated X Protein

OBJECTIVETo study the effects of Dipsacus total saponins on the ability of learning and memory and its mechanism of action.

METHODSForty rats were randomly divided into blank control group, model group, Dipsacus group and positive control group (n = 10), general situation of rats were observed, the ability of learning and memory of rats was tested by Square water maze, the activities of acetylcholinesterase (AChE)and choline acetyltransferase (ChAT) of hippocampus in rats were measured using double antibody sandwich method.

RESULTSDuring the period of treatment, general situation had no obvious change in model group, but general situation and the ability of activity were gradually improved in Dipsacus group and positive control group. Compared with blank control group, the swimming time was obviously prolonged and the number of mistakes was obviously increased at different time, the activity of AChE was significantly enhanced and the activity of ChAT was significantly decreased in model group. Compared with model group, the swimming time was obviously shortened and the number of mistakes was obviously reduced at different time, the activities of AChE were significantly decreased and the activities of ChAT were significantly enhanced in Dipsacus group and positive control group; Compared with positive control group, the swimming time and the number of mistakes at different time and the activities of AChE and ChAT had no significant difference in Dipsacus group.

CONCLUSIONDipsacus total saponins can improve the ability of learning and memory in Alzheimer' s disease(AD) rats, its mechanism of 'action may be related to regulating ACh metabolism of hippocampus.

Acetylcholine ; metabolism ; Acetylcholinesterase ; metabolism ; Alzheimer Disease ; drug therapy ; physiopathology ; Animals ; Choline O-Acetyltransferase ; metabolism ; Dipsacaceae ; chemistry ; Disease Models, Animal ; Hippocampus ; drug effects ; Learning ; drug effects ; Memory ; drug effects ; Rats ; Saponins ; pharmacology

The aim of the present study is to explore the interaction of nitric oxide (NO) and nicotinic acetylcholine receptor (nAChR) on learning and memory of rats. Rats were intracerebroventricularly (i.c.v.) injected with L-arginine (L-Arg, the NO precursor) (L-Arg group) or choline chloride (CC, an agonist of α7nAChR) (CC group), and with combined injection of L-Arg and CC (L-Arg+CC group), and methyllycaconitine (MLA, α7nAChR antagonist) or N(ω)-nitro-L-arginine methylester (L-NAME, nitric oxide synthase inhibitor) i.c.v. injected first and followed by administration of L-Arg combined with CC (MLA+L-Arg+CC group or L-NAME+L-Arg+CC group), respectively, and normal saline was used as control (NS group). The learning and memory ability of rats was tested with Y-maze; the level of NO and the expressions of neuronal nitric oxide synthase (nNOS) or α7nAChR in hippocampus were measured by NO assay kit, immunohistochemistry or Western blot. The results showed that compared with L-Arg group or CC group, the rats' learning and memory behavioral ability in Y-maze was observably enhanced and the level of NO, the optical density of nNOS-like immunoreactivity (LI) or α7nAChR-LI in hippocampus were significantly increased in L-Arg+CC group; Compared with L-Arg+CC group, the ability of learning and memory and the level of NO as well as the expressions of nNOS-LI or α7nAChR-LI were obviously decreased in MLA+L-Arg+CC group or in L-NAME+L-Arg+CC group. In conclusion, i.c.v. administration of L-Arg combined with CC significantly improved the action of the L-Arg or CC on the content of NO and the nNOS or α7nAChR expressions in hippocampus along with the learning and memory behavior of rats; when nNOS or α7nAChR was interrupted in advance, the effects of L-Arg combined with CC were also suppressed. The results suggest that there are probably synergistic effects between NO and nAChR on learning and memory.
Animals ; Enzyme Inhibitors ; pharmacology ; Hippocampus ; physiology ; Learning ; Memory ; NG-Nitroarginine Methyl Ester ; pharmacology ; Nitric Oxide ; physiology ; Nitric Oxide Synthase Type I ; physiology ; Rats ; alpha7 Nicotinic Acetylcholine Receptor ; physiology