The pre-synaptic sympathetic modulator role of adenosine was assessed by studying transmitter release following electrical depolarization of nerve endings from the rat mesenteric artery. Mesentery perfusion with exogenous adenosine exclusively inhibited the release of norepinephrine (NA) but did not affect the overflow of neuropeptide Y (NPY), establishing the basis for a differential pre-synaptic modulator mechanism. Several adenosine structural analogs mimicked adenosine's effect on NA release and their relative order of potency was: receptor antagonist only partially reduced the inhibitory action of adenosine, the combined co-application of the two antagonists fully blocked the adenosine-induced inhibition. Only the simultaneous blockade of the adenosine A 2A plus A 3 receptors with selective antagonists elicited a significant increase in NA overflow. H 89 reduced the release of both NA and NPY. We conclude that pre-synaptic A 2A and A 3 adenosine receptor activation modulates sympathetic co-transmission by exclusively inhibiting the release of NA without affecting immunoreactive (ir)-NPY and we suggest separate mechanisms for vesicular release modulation.

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Rasmussen’s aneurysm (RA) is a pseudoaneurysm of a pulmonary artery (AP), adjacent to or within a tuberculous cavity, appearing in 5% of these lesions. Its rupture might provoke massive hemoptysis (MH) with a near 50% mortality. The aim of this article is to report a case of massive hemoptysis following Rasmussen’s aneurysm. 52-year-old man with recent history of hospitalization due to pneumonia associated to influenza A and decompensated hyperthyroidism, presents outpatient chest radiograph with signs of hyperinflation and scarring apical opacities, the patient returned to the hospital due to sharp pain of left hemi thorax during inspiration accompanied with bloody sputum, asthenia and non-quantified weight loss. He evolves to frank MH, requiring endotracheal intubation managed in the intensive care unit (ICU). Chest computed tomography (CT) reported ground-glass opacity, nodules with a tendency to cavitation, tree-inbud pattern in agreement with inflammation and infection, active TB is considered, and truncus of PA with vascular lesion suggestive of aneurysm dependent on pulmonary circulation, possibly RA. Fibrobronchoscopy reported signs of old and recent bleeding of left bronchial tree, probably of the lingula, blood clots in right bronchial tree. Molecular study and TB cultures was negative. Endovascular procedure with arteriography was carried out, revealing amputation of left distal segmental PA carrying the pseudoaneurysm with complete regression, discarding embolization RA It must be considered among the differential diagnoses of MH, especially on patients with pulmonary TB complications, such as the reported case. Due to its associated increased mortality, once RA is identified, it must be either endovascularly or surgically eradicated.