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Rial RV, Canellas F, Akaârir M, Rubiño JA, Barceló P, Martín A, Gamundí A, Nicolau MC. The Birth of the Mammalian Sleep. BIOLOGY 2022; 11:biology11050734. [PMID: 35625462 PMCID: PMC9138988 DOI: 10.3390/biology11050734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/05/2022] [Indexed: 11/16/2022]
Abstract
Simple Summary Mammals evolved from reptiles as a consequence of an evolutionary bottleneck. Some diurnal reptiles extended their activity, first to twilight and then to the entire dark time. This forced the change of the visual system. Pursuing maximal sensitivity, they abandoned the filters protecting the eyes against the dangerous diurnal light, which, in turn, forced immobility in lightproof burrows during light time. This was the birth of the mammalian sleep. Then, the Cretacic-Paleogene extinction of dinosaurs leaved free the diurnal niche and allowed the expansion of a few early mammals to diurnal life and the high variability of sleep traits. On the other hand, we propose that the idling rest is a state showing homeostatic regulation. Therefore, the difference between behavioral rest and wakeful idling is rather low: both show quiescence, raised sensory thresholds, reversibility, specific sleeping-resting sites and body positions, it is a pleasing state, and both are dependent of circadian and homeostatic regulation. Indeed, the most important difference is the unconsciousness of sleep and the consciousness of wakeful idling. Thus, we propose that sleep is a mere upgrade of the wakeful rest, and both may have the same function: guaranteeing rest during a part of the daily cycle. Abstract Mammals evolved from small-sized reptiles that developed endothermic metabolism. This allowed filling the nocturnal niche. They traded-off visual acuity for sensitivity but became defenseless against the dangerous daylight. To avoid such danger, they rested with closed eyes in lightproof burrows during light-time. This was the birth of the mammalian sleep, the main finding of this report. Improved audition and olfaction counterweighed the visual impairments and facilitated the cortical development. This process is called “The Nocturnal Evolutionary Bottleneck”. Pre-mammals were nocturnal until the Cretacic-Paleogene extinction of dinosaurs. Some early mammals returned to diurnal activity, and this allowed the high variability in sleeping patterns observed today. The traits of Waking Idleness are almost identical to those of behavioral sleep, including homeostatic regulation. This is another important finding of this report. In summary, behavioral sleep seems to be an upgrade of Waking Idleness Indeed, the trait that never fails to show is quiescence. We conclude that the main function of sleep consists in guaranteeing it during a part of the daily cycle.
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Affiliation(s)
- Rubén V. Rial
- Laboratori de Neurofisiologia del Son i dels Ritmes Biològics, Grup de Recerca Neurofisiologia del Son i Ritmes Biològics, Department of Biologia, Universitat de les Illes Balears, Ctra Valldemossa, km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; (F.C.); (M.A.); (J.A.R.); (P.B.); (A.M.); (A.G.); (M.C.N.)
- IdISBa, Institut d’Investigació Sanitària de les Illes Balears, Hospital Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- IUNICS, Institut Universitari d’Investigació en Ciències de la Salut, Hospital Universitary Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- Correspondence: ; Tel.: +34-971-173-147; Fax: +34-971-173-184
| | - Francesca Canellas
- Laboratori de Neurofisiologia del Son i dels Ritmes Biològics, Grup de Recerca Neurofisiologia del Son i Ritmes Biològics, Department of Biologia, Universitat de les Illes Balears, Ctra Valldemossa, km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; (F.C.); (M.A.); (J.A.R.); (P.B.); (A.M.); (A.G.); (M.C.N.)
- IdISBa, Institut d’Investigació Sanitària de les Illes Balears, Hospital Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- IUNICS, Institut Universitari d’Investigació en Ciències de la Salut, Hospital Universitary Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
| | - Mourad Akaârir
- Laboratori de Neurofisiologia del Son i dels Ritmes Biològics, Grup de Recerca Neurofisiologia del Son i Ritmes Biològics, Department of Biologia, Universitat de les Illes Balears, Ctra Valldemossa, km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; (F.C.); (M.A.); (J.A.R.); (P.B.); (A.M.); (A.G.); (M.C.N.)
- IdISBa, Institut d’Investigació Sanitària de les Illes Balears, Hospital Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- IUNICS, Institut Universitari d’Investigació en Ciències de la Salut, Hospital Universitary Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
| | - José A. Rubiño
- Laboratori de Neurofisiologia del Son i dels Ritmes Biològics, Grup de Recerca Neurofisiologia del Son i Ritmes Biològics, Department of Biologia, Universitat de les Illes Balears, Ctra Valldemossa, km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; (F.C.); (M.A.); (J.A.R.); (P.B.); (A.M.); (A.G.); (M.C.N.)
- IdISBa, Institut d’Investigació Sanitària de les Illes Balears, Hospital Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- IUNICS, Institut Universitari d’Investigació en Ciències de la Salut, Hospital Universitary Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
| | - Pere Barceló
- Laboratori de Neurofisiologia del Son i dels Ritmes Biològics, Grup de Recerca Neurofisiologia del Son i Ritmes Biològics, Department of Biologia, Universitat de les Illes Balears, Ctra Valldemossa, km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; (F.C.); (M.A.); (J.A.R.); (P.B.); (A.M.); (A.G.); (M.C.N.)
- IdISBa, Institut d’Investigació Sanitària de les Illes Balears, Hospital Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- IUNICS, Institut Universitari d’Investigació en Ciències de la Salut, Hospital Universitary Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
| | - Aida Martín
- Laboratori de Neurofisiologia del Son i dels Ritmes Biològics, Grup de Recerca Neurofisiologia del Son i Ritmes Biològics, Department of Biologia, Universitat de les Illes Balears, Ctra Valldemossa, km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; (F.C.); (M.A.); (J.A.R.); (P.B.); (A.M.); (A.G.); (M.C.N.)
- IdISBa, Institut d’Investigació Sanitària de les Illes Balears, Hospital Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- IUNICS, Institut Universitari d’Investigació en Ciències de la Salut, Hospital Universitary Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
| | - Antoni Gamundí
- Laboratori de Neurofisiologia del Son i dels Ritmes Biològics, Grup de Recerca Neurofisiologia del Son i Ritmes Biològics, Department of Biologia, Universitat de les Illes Balears, Ctra Valldemossa, km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; (F.C.); (M.A.); (J.A.R.); (P.B.); (A.M.); (A.G.); (M.C.N.)
- IdISBa, Institut d’Investigació Sanitària de les Illes Balears, Hospital Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- IUNICS, Institut Universitari d’Investigació en Ciències de la Salut, Hospital Universitary Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
| | - M. Cristina Nicolau
- Laboratori de Neurofisiologia del Son i dels Ritmes Biològics, Grup de Recerca Neurofisiologia del Son i Ritmes Biològics, Department of Biologia, Universitat de les Illes Balears, Ctra Valldemossa, km 7.5, 07122 Palma de Mallorca, Illes Balears, Spain; (F.C.); (M.A.); (J.A.R.); (P.B.); (A.M.); (A.G.); (M.C.N.)
- IdISBa, Institut d’Investigació Sanitària de les Illes Balears, Hospital Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
- IUNICS, Institut Universitari d’Investigació en Ciències de la Salut, Hospital Universitary Son Espases, 07120 Palma de Mallorca, Illes Balears, Spain
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Jensen B, Christoffels VM. Reptiles as a Model System to Study Heart Development. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a037226. [PMID: 31712265 DOI: 10.1101/cshperspect.a037226] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A chambered heart is common to all vertebrates, but reptiles show unparalleled variation in ventricular septation, ranging from almost absent in tuataras to full in crocodilians. Because mammals and birds evolved independently from reptile lineages, studies on reptile development may yield insight into the evolution and development of the full ventricular septum. Compared with reptiles, mammals and birds have evolved several other adaptations, including compact chamber walls and a specialized conduction system. These adaptations appear to have evolved from precursor structures that can be studied in present-day reptiles. The increase in the number of studies on reptile heart development has been greatly facilitated by sequencing of several genomes and the availability of good staging systems. Here, we place reptiles in their phylogenetic context with a focus on features that are primitive when compared with the homologous features of mammals. Further, an outline of major developmental events is given, and variation between reptile species is discussed.
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Affiliation(s)
- Bjarke Jensen
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC 1105AZ, Amsterdam, The Netherlands
| | - Vincent M Christoffels
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC 1105AZ, Amsterdam, The Netherlands
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Kroneman JGH, Faber JW, Schouten JCM, Wolschrijn CF, Christoffels VM, Jensen B. Comparative analysis of avian hearts provides little evidence for variation among species with acquired endothermy. J Morphol 2019; 280:395-410. [PMID: 30667083 PMCID: PMC6590421 DOI: 10.1002/jmor.20952] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 12/19/2018] [Accepted: 01/01/2019] [Indexed: 12/12/2022]
Abstract
Mammals and birds acquired high performance hearts and endothermy during their independent evolution from amniotes with many sauropsid features. A literature review shows that the variation in atrial morphology is greater in mammals than in ectothermic sauropsids. We therefore hypothesized that the transition from ectothermy to endothermy was associated with greater variation in cardiac structure. We tested the hypothesis in 14 orders of birds by assessing the variation in 15 cardiac structures by macroscopic inspection and histology, with an emphasis on the atria as they have multiple features that lend themselves to quantification. We found bird hearts to have multiple features in common with ectothermic sauropsids (synapomorphies), such as the presence of three sinus horns. Convergent features were shared with crocodylians and mammals, such as the cranial offset of the left atrioventricular junction. Other convergent features, like the compact organization of the atrial walls, were shared with mammals only. Pacemaker myocardium, identified by Isl1 expression, was anatomically node‐like (Mallard), thickened (Chicken), or indistinct (Lesser redpoll, Jackdaw). Some features were distinctly avian, (autapomorphies) including the presence of a left atrial antechamber and the ventral merger of the left and right atrial auricles, which was found in some species of parrots and passerines. Most features, however, exhibited little variation. For instance, there were always three systemic veins and two pulmonary veins, whereas among mammals there are 2–3 and 1–7, respectively. Our findings suggest that the transition to high cardiac performance does not necessarily lead to a greater variation in cardiac structure.
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Affiliation(s)
- Jelle G H Kroneman
- Department of Pathobiology, Anatomy and Physiology division, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.,Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
| | - Jaeike W Faber
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
| | - Jacobine C M Schouten
- Department of Pathobiology, Anatomy and Physiology division, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Claudia F Wolschrijn
- Department of Pathobiology, Anatomy and Physiology division, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Vincent M Christoffels
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
| | - Bjarke Jensen
- Department of Medical Biology, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam UMC, Meibergdreef 15, 1105AZ, Amsterdam, The Netherlands
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Brashears JA, Hoffman TCM, DeNardo DF. Modeling the costs and benefits associated with the evolution of endothermy using a robotic python. J Exp Biol 2017; 220:2409-2417. [PMID: 28679794 DOI: 10.1242/jeb.151886] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/18/2017] [Indexed: 11/20/2022]
Abstract
Endothermy provides considerable benefits to an organism but requires large energy investment. To understand potential driving forces that would lead to the evolution of endothermy, it is important to understand the energy costs and potential benefits of intermediate steps between ectothermy and homeothermic endothermy as well as the influences of environmental conditions on energetic costs. However, efforts to examine intermediate conditions are greatly limited by the predominant natural dichotomy between ectothermy and endothermy. Facultative endothermy by brooding pythons provides a fortunate study system where endothermy is beneficial but not essential. As one cannot control the extent of energy investment in heat production by a female python, we created an artificial snake with controllable heating capability. This enabled us to determine the energetic costs of maintaining a clutch at a preferred temperature, and to determine the relative thermal benefit of limited energy-producing capability (i.e. 50% of the required energy to maintain the preferred developmental temperature). We manipulated the pseudoserpent's clutch size (5, 10, 15 eggs), diel ambient temperature cycle (2, 4, 6°C) and insulation (with and without) at each of these power levels: unlimited power, half required power and no power. We found no significant effect of clutch size on either power requirements or developmental temperature. Energy requirements increased with the amplitude of the diel cycle and decreased with the addition of insulation, while the quality of the thermal environment decreased with the amplitude of the diel cycle. Interestingly, the quality of the thermal environment also decreased with the addition of insulation. We discuss these results within the context of the reproductive model of the evolution of endothermy.
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Affiliation(s)
- J Alex Brashears
- Natural Sciences Department, LaGuardia Community College, Long Island City, NY 11101, USA .,School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Ty C M Hoffman
- School of Mathematical and Natural Sciences, New College of Interdisciplinary Arts and Sciences, Arizona State University at the West Campus, Phoenix, AZ 85069, USA
| | - Dale F DeNardo
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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