In this study, we assessed the effects of oxytocin (OT) on mean arterial blood pressure (MAP), heart rate (HR), and locomotor activity (LA) in male spontaneous hypertensive rats (SHR) and Sprague-Dawley (SDR) controls using telemetry. OT was given by intravenous injections of 0.1, 0.2 or 0.4mg/kg to assess short term acute effects or by daily subcutaneous injections of 0.5 or 1.0mg/kg for 5 days. Compared to the saline infusion, (i) intravenous OT, regardless of concentration, increased MAP in SHR and SDR, (ii) HR increased, but was periodically lower in both strains with 0.2 or 0.4mg/kg, and (iii) no effects of OT on LA were observed. Subcutaneous injections demonstrated that (i) 1.0mg/kg for 5days lowered diurnal MAP and HR in SDR and SHR, persisting for 6 days, (ii) 1.0mg/kg decreased nocturnal HR in SDR, (iii) 0.5 and 1.0mg/kg decreased MAP with minor effects on HR in the SHR, and lastly (iv) OT decreased LA mainly during the diurnal cycle in both strains. Our main results show that OT induces significant beneficial effects on cardiovascular function over several diurnal and nocturnal cycles in the SHR, with the most prominent effect being a robust decrease in MAP.
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http://dx.doi.org/10.1016/j.pathophys.2016.03.003 | DOI Listing |
Med Vet Entomol
December 2024
Laboratory of Insects of Forensic Importance, Department of Zoology, Universidade Federal de Pernambuco, Recife, Brazil.
The nocturnal behaviour and reproduction patterns of Sarcophagidae species during the scotophase are largely unexplored for species in the Neotropical region. The aim of this study was to assess the light regimes under which females of Peckia (Peckia) chrysostoma (Wiedemann, 1830) and Peckia (Sarcodexia) lambens (Wiedemann, 1830) would larviposit and understand how these variables influence intrauterine development in these flies. The experiments were conducted in an experimental room (lux = 100) in two independent experiments: I.
View Article and Find Full Text PDFJ Biol Rhythms
December 2024
Department of Cell and Chemical Biology, Leiden University Medical Center, Leiden, The Netherlands.
In both diurnal and nocturnal species, the neurons in the suprachiasmatic nucleus (SCN) generate a daily pattern in which the impulse frequency peaks at midday and is lowest during the night. This pattern, common to both day-active and night-active species, has led to the long-standing notion that their functional difference relies merely on a sign reversal in SCN output. However, recent evidence shows that the response of the SCN to the animal's physical activity is opposite in nocturnal and diurnal animals.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
Institute of Coastal Environmental Pollution Control, College of Environmental Science and Engineering, Key Laboratory of Marine Environment and Ecology, Ocean University of China, Qingdao 266100, China; Sanya Oceanographic Institution, Ocean University of China, Sanya 57200, China. Electronic address:
The pollution of triadimefon (TDF) fungicides significantly hinders the "One Health" frame achievement. However, the enantioselective effects of chiral TDF on the circadian rhythm of fish remained unclear. Herein, TDF enantiomers (R(-)-TDF and S(+)-TDF) and racemic Rac-TDF were selected to investigate their enantioselective effects and mechanisms on circadian rhythm of goldfish (Carassius auratus) at an environmentally-relevant concentration (100 µg L⁻¹).
View Article and Find Full Text PDFJ Neurophysiol
December 2024
Dept. of Biol., University of Massachusetts Amherst, , Amherst, MA.
Lab rodent species commonly used to study the visual system and its development (hamsters, rats, and mice) are crepuscular/nocturnal, altricial, and possess simpler visual systems than carnivores and primates. To widen the spectra of studied species, here we introduce an alternative model, the Chilean degu (). This diurnal, precocial Caviomorph rodent has a cone enriched, well-structured retina, and well-developed central visual projections.
View Article and Find Full Text PDFAm J Primatol
January 2025
Anthropology Department, University of Florida, Gainesville, Florida, USA.
The study of primate auditory morphology is a significant area of interest for comparative anatomists, given the phylogenetic relationships that link primate hearing and the morphology of these auditory structures. Extensive literature addresses the form-to-function relationship of the auditory system (outer, middle, and inner ear) in primates and, by extension, provides insight into the auditory system of extinct primates and even modern humans. We add to this literature by describing the ontogenetic trajectory of the middle ear cavity and ossicular chain (malleus, incus, and stapes) due to their critical role in relaying auditory stimuli for interpretation.
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