Frozen aortic segments from the thoracic aorta were cut into 14mm thick sections

TU or NBTI were completely antagonised by SCH 58261. In contrast, electricallyevoked tritium overflow from SHR mesenteric arteries was unaffected by pharmacological manipulation of endogenous adenosine levels. Data Analysis Measurement of drug effects on electrically-evoked tritium overflow. Electrically-evoked tritium overflow from artery segments GW 5074 incubated with -noradrenaline has been shown to reflect action potential-evoked neuronal noradrenaline release and drug-induced changes in evoked tritium overflow are assumed to reflect changes in neuronal noradrenaline release. Effects of drugs added after S1 on electrically-evoked tritium overflow were evaluated as ratios of the overflow elicited by S2 and the overflow elicited by S1. S2/S1 ratios obtained in individual experiments in which a test compound A was added after S1 were calculated as a percentage of the respective mean ratio in the appropriate control group. When the interaction of A, added after S1, and a drug B added 5 min before S2, was studied, the “appropriate control”was a group in which A alone was used. Laser Scanning Confocal Microscopy images quantification. Quantitative analysis of confocal z-stacks im- ages was performed using image analysis software. Briefly, a sequential routine was designed and developed to analyse each fluorescent signal used. PAQI software measured the surface area and strength of the fluorescence signal marking the postganglionic nerves, the surface area and strength of the fluorescence signal marking the receptors and determined the surface area of attachment of the receptors on the nerves as well as the intensity of fluorescence of the receptors on nerves. Quantification of the e-derivatives formed in collected artery superfusates. The amount of adenine nucleotides and adenosine in each collected sample was estimated from calibration curves of purine standards, run with every set of 20 samples. Statistics. Results are expressed as mean6s.e.m. and n denotes the number of tissue segments. Differences of means were compared for significance using one- or two-way ANOVA, followed by post-hoc Holm-Sidak’s multicomparison t test. A P ATP and adenosine levels in WKY and SHR mesenteric arteries Noradrenaline/ATP co-transmission has been demonstrated to occur in mesenteric artery. Endogenous levels of ATP and adenosine were significantly higher in superfusates from SHR mesenteric arteries, comparatively to those of WKY, both under basal conditions and after electrical stimulation. Only minute amounts of ADP and AMP were found Adenosine Tonus Impairment in Hypertension . Moreover, stimulation increased ATP released amounts comparatively to the amounts observed in basal conditions, but only in SHR tissues. Surprisingly, adenosine levels, before and after stimulation, were similar in arteries from both strains, although still higher than those of ATP. Localization of adenosine A1 and A2A receptors in vascular sympathetic neurons in PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19661801 the adventitia of WKY and SHR mesenteric arteries Effects of adenosine A1 and A2A receptor agonists on vascular sympathetic neurotransmission CPA inhibited electrically-evoked tritium overflow in mesenteric arteries from both strains. This inhibition was more pronounced in WKY than in SHR. Conversely, the selective adenosine A2A receptor agonist, CGS 21680, facilitated tritium overflow to similar extent: 123.6465.18% and 121.6267.73% in WKY and SHR mesenteric arteries, respectively. Effects elicited by adenosine receptor agonis