AIM To investigate whether there is vasodilator nerve innervation in rat hind limb and what the nature of vasodilator nerve is. METHODS Wistar rats were treated with reserpine 1 mg?kg -1 ip at 24 h before experiment. The rats were pithed and the hind limb vascular bed was perfused with Krebs-Henseleite solution containing 1 mmol?L -1 phenylephrine at 2 ml?min -1 speed. The hind limb perfused pressure (HPP) as a main index was continuously recorded. Spinal cord electrical stimulation (SES) was repeatedly applied via an electrode at L 1～2 level of lumber vertebra. The various tool drugs were administered by iv or infusion by added to persusion solution. The data is expressed as decrease percentages of HPP increased by continuous infusion of phenylephrine. RESULTS HPP was increased from (5 7?1 5) to (21 6?3 7) kPa ( n =37) after phenylephrine perfusion. SES caused a fall of HPP in frequency dependent and voltage dependent manner. An optimum parameters of SES (10 Hz, 50 V and 1 msec) was selected to observe effects of various tool drugs on depressor response of HPP to SES. Tetrotodoxin (0 3 ?mol?L -1 ) abolished the effect completely. L NAME (10 ?mol?L -1 ), a NO synthase inhibitor, had no effect. Ganglion blocker arfonad (110 mg?kg -1 , iv, M R blocker atropine (10 ?mol?L -1 ), ? receptor blocker propranolol (1 ?mol?L -1 ) and P 1 receptor blocker aminophylline (10 ?mol?L -1 ) had also no effect. Glibenclamide (0 1 mmol?L -1 ), an ATP sensitive K + channel blocker, markedly abolished and slightly reversed the effect. CONCLUTION The nonadrenergic noncholinergic vasodilator nerve exists in rat hind limb and is not nitroxidergic or purinergic nerve. This nerve may be peptidergic nerve which releases some peptide such as CGRP and the major mechanism of vasodilatation probably activates the ATP sensitive K + channel.

Ceramide (Cer) is a second messenger produced by the degradation of plasma membrane phospholipids in cells. It is an essential lipid mediator for normal cellular function, composed of sphingosine and different chains of fatty acids. Its receptors are widely present in red blood cells, endothelial cells, glial cells, immune cells, and nerve cells, and participate in various pathophysiological processes such as oxidative stress, inflammatory response, signal pathway transduction, and immune regulation. Many studies have confirmed that the increase of Cer level is related to cardiovascular disease, type 2 diabetes and lipid metabolism. Ceramide score can be used as a tool to evaluate the severity and prognosis of cardiovascular events. However, there is limited research on the impact of Cer on acute ischemic stroke (AIS). This article aims to elucidate the role of Cer and its impact on the occurrence, development, and prognosis of AIS.

Objective:To investigate the distribution of potential suitable habitats for Ixodes persulcatus in Heilongjiang Province during different climatic periods. Methods:The geographical location data of Ixodes persulcatus in Heilongjiang Province from 1980 to 2023 were collected through literature search and field ecological investigation. The environmental factor variables were downloaded from the WorldClim website and the Resource and Environmental Science and Data Platform. A combination of SDMtune, ENMTools packages, and the maximum entropy (MaxEnt) model were used to predict the potential habitats of Ixodes persulcatus in Heilongjiang Province during different climatic periods and determine its dominant environmental factors. Among them, the time range of historical climatic period data was 1970 - 2000. The future climatic period data (2021 - 2040, 2041 - 2060) were selected as the low forcing scenario (SSP126 scenario) of the shared socioeconomic pathways (SSP) in the Beijing Climate Center - Climate System Model version 2-Medium Resolution, to simulate the impact of global warming on the distribution of potential habitats for Ixodes persulcatus in Heilongjiang Province. Results:A total of 83 geographical distribution sites of Ixodes persulcatus in Heilongjiang Province were obtained. After screening, 10 environmental factors were included in the MaxEnt model. Among them, the cumulative contribution percentage of annual precipitation, average annual temperature, and vegetation type was 67.3%. Compared with historical climatic period, the total potential habitats of Ixodes persulcatus in Heilongjiang Province increased from 29.81 × 10 4 km 2 to 32.24 × 10 4 km 2 in 2041 - 2060. The center of potential habitats moved to 47.75° N, and 128.66° E, with a northwest offset of 126.07° and a migration distance of 45.83 km. Conclusion:With global climate warming, the total potential habitats of Ixodes persulcatus in Heilongjiang Province has increased, showing an overall trend of migration to the northwest.