Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time, and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space. While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes, vast areas of the tropics remain understudied. In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity, but it remains among the least known forests in America and is often underrepresented in biodiversity databases. To worsen this situation, human-induced modifications may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge, it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

The role of histamine in human penile erection

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOTo investigate the relaxant action of histamine on human corpus cavernosum in vitro and the erectile response caused by the intracavernous injection of histamine in patients with psychogenic impotence. Patients and methods Human corpus cavernosum (HCC) tissue was cut into strips of approximately 2 cm and suspended in a cascade bioassay. The strips were then superfused with oxygenated and warmed Krebs solution and precontracted with noradrenaline (3 mu M). Glyceryl trinitrate, acetylcholine and histamine were injected as a single bolus in the absence or in the presence of mepyramine and cimetidine. For the in vivo studies, histamine (30-60 mu g) was injected intracavernously as a single bolus into the right corpus cavernosum 1 cm from the balamo-preputial sulcus. Similar protocols were carried out for papaverine (50 mg). The erectile response was divided into four grades: no response, tumescence, partial and full erection. Results In vitro studies demonstrated that histamine (3-100 mu g) caused dose-dependent relaxation of the HCC strips which was significantly inhibited by cimetidine (5-10 mu M). The histamine H-1 receptor antagonist mepyramine (1 mu M) potentiated histamine-induced relaxation. The co-infusion of both mepyramine and cimetidine did not abolish histamine-induced relaxation. When injected intracavernously in humans, histamine (30 mu g) caused full erection in 13% of the patients, whereas 87% had partial erection or tumescence. A higher dose of histamine (60 mu g) caused full erection in 26% of the patients and 74% had partial erection or tumescence. Papaverine induced full erection in the majority of patients (66%). In contrast to papaverine, the duration of erection induced by histamine was markedly shorter (mean 200 and 6.5 min, respectively). The penile erections induced by papaverine were associated with complications such as pain, haematoma and priapism. Histamine did not induce any complications. Treatment of eight male patients with psychogenic impotence with the histamine H-1 receptor antagonist astemizol (10 mg orally once daily for 1 week) did not affect histamine-induced erectile responses. Conclusion These results indicate that histamine may play a role in human penile erection. The erection-promoting action of histamine is probably due to H-2 receptor activation, although another histamine receptor, possibly H-3, also seems to be involved. This study suggests that histamine could be a valuable tool in the diagnosis of erectile dysfunctionBlackwell Science752220224FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOsem informaçãoOxfor

Pharmacological characterization of rabbit corpus cavernosum relaxation mediated by the tissue kallikrein-kinin system

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOThe roles of the tissue kallikrein-kinin system and nitric oxide (NO) release in Phoneutria nigriventer venom-induced relaxations of rabbit corpus cavernosum (RbCC) smooth muscle have been investigated by use of a bioassay cascade. 2 Phoneutria nigriventer venom (10-30 mu g), porcine pancreatic kallikrein (100 mu), rabbit urinary kallikrein (10 mu), bradykinin (BK, 0.3-3 nmol), acetylcholine (ACh, 0.3-30 nmol) and glyceryl trinitrate (GTN, 0.5-10 nmol) caused relaxations of the RbCC strips. Captopril (1 mu M) substantially potentiated Phoneutria nigriventer venom- and BK-induced RbCC relaxations without affecting those elicited by GTN. 3 The bradykinin B-2 receptor antagonist, Hoe 140 (D-Arg-[Hyp(3),Thi(5), D-Tic(7),Oic(8)]-BK, 50 nM), aprotinin (10 mu g ml(-1)) and the tissue kallikrein inhibitor, Pro-Phe-Aph-Ser-Val-Gln-NH2 (KIZD-06, 1.3 mu M) significantly inhibited Phoneutria nigriventer venom-induced RbCC relaxations, without affecting those provoked by GTN and ACh. The B-1 receptor antagonist, [Leu(9)]des Arg(10)BK (0.5 mu M) and soybean trypsin inhibitor (SBTI, 10 mu g ml(-1)) had no effect on Phoneutria nigriventer venom-induced RbCC relaxations. 4 The relaxations induced by Phoneutria nigriventer venom, porcine pancreas kallikrein, BK and ACh were significantly inhibited by N-omega-nitro-L-arginine methyl ester (L-NAME, 10 mu M) but not by D-NAME (10 mu M). L-NAME did not affect GTN-induced relaxations. L-Arginine (300 mu M), but not D-arginine (300 mu M), significantly reversed the inhibitory effect of L-NAME. 5 Our results indicate that Phoneutria nigriventer venom activates the tissue kallikrein-kininogen-kinin system in RbCC strips leading to NO release and suggest a functional role for this system in penile erection11318186FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOsem informaçã