A5072543185- Physiological and biochemical adaptations
- Neurobiology and Insect Physiology Research
- Neuroscience of respiration and sleep
- Sulfur Compounds in Biology
- Nitric Oxide and Endothelin Effects
- High Altitude and Hypoxia
- Heart Rate Variability and Autonomic Control
- Turtle Biology and Conservation
- Meat and Animal Product Quality
- Cardiovascular, Neuropeptides, and Oxidative Stress Research
- Parasite Biology and Host Interactions
- Neuroendocrine regulation and behavior
- Circadian rhythm and melatonin
- Renin-Angiotensin System Studies
- Neuropeptides and Animal Physiology
- Zebrafish Biomedical Research Applications
- Receptor Mechanisms and Signaling
- Fish Ecology and Management Studies
- Pharmacological Effects and Assays
- Aquaculture Nutrition and Growth
- Pain Mechanisms and Treatments
- Hormonal and reproductive studies
- Heme Oxygenase-1 and Carbon Monoxide
- Glaucoma and retinal disorders
- Trauma Management and Diagnosis
Aarhus University
2009-2021
University of Exeter
2015
Indiana University School of Medicine
2008-2012
Indiana University South Bend
2012
University of Oslo
2012
Indiana University
2008
University of Notre Dame
2008
Indiana University – Purdue University Indianapolis
2008
Universidade Estadual Paulista (Unesp)
2005-2007
Hydrogen sulfide (H(2)S) is rapidly emerging as a biologically significant signaling molecule. Studies published before 2000 report low or undetectable H(2)S (usually total sulfide) levels in blood plasma, whereas recent work has reported concentrations between 10 and 300 microM, suggesting it acts circulating signal. In the first series of experiments, we used recently developed polarographic sensor to measure baseline level endogenous gas turnover exogenous real time from numerous animals,...
O2 chemoreceptors elicit cardiorespiratory reflexes in all vertebrates, but consensus on O2-sensing signal transduction mechanism(s) is lacking. We recently proposed that hydrogen sulfide (H2S) metabolism involved sensing vascular smooth muscle. Here, we examined the possibility H2S an sensor trout where first pair of gills a primary site aquatic and homolog mammalian carotid body. Intrabuccal injection unanesthetized produced dose-dependent bradycardia increased ventilatory frequency...
Endogenous hydrogen sulfide (H<sub>2</sub>S) is involved in the regulation of vascular tone. We hypothesized that lowering calcium and opening potassium (K) channels as well calcium-independent mechanisms are H<sub>2</sub>S-induced relaxation rat mesenteric small arteries. Amperometric recordings revealed free [H<sub>2</sub>S] after addition to closed tubes sodium hydrosulfide (NaHS), Na<sub>2</sub>S, GYY4137 [<i>P</i>-(4-methoxyphenyl)-<i>P</i>-4-morpholinyl-phosphinodithioic acid] were,...
The intrinsic heart rate of most vertebrates studied, including humans, is elevated during digestion, suggesting that a nonadrenergic-noncholinergic factor contributes to the postprandial tachycardia. regulating factor, however, remains elusive and difficult identify. Pythons can ingest very large meals, digestion associated with marked rise in metabolism sustained for several days. metabolic causes more than doubling fourfold cardiac output. This makes python an interesting model...
Pythons exhibit a doubling of heart rate when metabolism increases several times during digestion. Pythons, therefore, represent promising model organism to study autonomic cardiovascular regulation the postprandial state, and previous studies show that tachycardia is governed by release vagal tone as well pronounced stimulation from nonadrenergic, noncholinergic (NANC) factors. Here we infusion plasma digesting donor pythons elicit marked in fasting snakes, demonstrating NANC factor resides...
Control of the heart rate and cardiorespiratory interactions (CRI) is predominantly parasympathetic in all jawed vertebrates, with sympathetic nervous system having some influence tetrapods. Respiratory sinus arrhythmia (RSA) has been described as a solely mammalian phenomenon but respiration-related beat-to-beat control fish reptiles. Though they are both important, relative roles feed-forward central peripheral reflexes generating CRI vary between groups fishes probably other vertebrates....
Hypoxic pulmonary vasoconstriction (HPV) is an adaptive response that diverts blood flow from poorly ventilated and hypoxic areas of the lung to more well-ventilated parts. This important for local matching perfusion ventilation improves gas exchange efficiency. HPV ancient highly conserved response, expressed in respiratory organs all vertebrates, including lungs mammals, birds, reptiles; amphibian skin; fish gills. The mechanism underlying how cells sense low Po(2) remains elusive. In...
SUMMARY Turtles of the genus Trachemys show a remarkable ability to survive prolonged anoxia. This is achieved by strong metabolic depression, redistribution blood flow and high levels antioxidant defence. To understand whether nitric oxide (NO), major regulator vasodilatation oxygen consumption, may be involved in adaptive response anoxia, we measured NO metabolites (nitrite, S-nitroso, Fe-nitrosyl N-nitroso compounds) plasma red cells venous arterial scripta turtles during normoxia after...
The high blood pressure in giraffe leg arteries renders giraffes vulnerable to edema. We investigated 11 whether large and small the legs tight fascia protect capillaries. Ultrasound imaging of foreleg anesthetized ex vivo examination revealed abrupt thickening arterial wall a reduction its internal diameter just below elbow. At distal this narrowing, artery constricted spontaneously response norepinephrine intravascular recordings dynamic, viscous drop along artery. Histology isolated...
SUMMARY Synbranchus marmoratus is a facultative air-breathing fish, which uses its buccal cavity as well gills for air-breathing. S. shows very pronounced tachycardia when it surfaces to air-breathe. An elevation of heart rate decreases cardiac filling time and therefore may cause decline in stroke volume (VS), but this can be compensated by an increase venous tone maintain volume. Thus, the study on was undertaken investigate how function are affected during To end we measured output(Q̇),...
Incubation of heat-denatured plasma from the rattlesnake Crotalus atrox with trypsin generated a bradykinin (BK) that contained two amino acid substitutions (Arg1 --> Val and Ser6 Thr) compared mammalian BK. Bolus intra-arterial injections synthetic BK (0.01-10 nmol/kg) into anesthetized rattlesnake, durissus terrificus, produced pronounced concentration-dependent increase in systemic vascular conductance (Gsys). This caused fall arterial blood pressure (Psys) an flow. Heart rate stroke...
The effects of adrenergic stimulation on mean circulatory filling pressure (MCFP), central venous (P(CV)) and stroke volume (Vs), as well the altered MCFP through changes blood were investigated in rattlesnakes (Crotalus durissus). is an estimate upstream driving towards heart determined by activity smooth muscle cells veins (venous tone). can be plateau P(CV) during a total occlusion flow from heart. Vs decreased significantly when was lowered reducing anaesthetised snakes, whereas...
Low O 2 levels in the lungs of birds and mammals cause constriction pulmonary vasculature that elevates resistance to blood flow increases pressure. This hypoxic vasoconstriction (HPV) diverts from poorly ventilated areas lung more well-ventilated parts is considered important for local matching ventilation perfusion. In present study, effects acute hypoxia on systemic flows pressures were measured four species anesthetized reptiles with diverse structures heart morphologies: varanid lizards...
Systemic vascular resistance (R(sys)) of freshwater turtles increases substantially during anoxia, but the underlying mechanisms are not fully understood. We investigated whether hydrogen sulfide (H(2)S), an endogenously produced metabolite believed to be O(2) sensor/transducer vasomotor tone, contributes increased R(sys) anoxic red-eared slider (Trachemys scripta). Vascular infusion H(2)S donor NaHS in anesthetized at 21 degrees C and recovered normoxic 5 revealed a potent vasoconstrictor...
Digestion of large meals in pythons produces substantial increases heart rate and cardiac output, as well a dilation the mesenteric vascular bed leading to intestinal hyperemia, but mediators these effects are unknown. Bolus intra-arterial injections python neurotensin ([His 3 , Val 4 Ala 7 ]NT) (1 − 1,000 pmol/kg) into anesthetized ball Python regius ( n = 7) produced dose-dependent vasodilation that was associated with decrease systemic pressure (P sys ) increase blood flow (Q ). There no...