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Trejo-Sánchez I, Pérez-Monter C, Huerta-Pacheco S, Gutiérrez-Ospina G. Male Ejaculatory Endophenotypes: Revealing Internal Inconsistencies of the Concept in Heterosexual Copulating Rats. Front Behav Neurosci 2020; 14:90. [PMID: 32670030 PMCID: PMC7332778 DOI: 10.3389/fnbeh.2020.00090] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 05/14/2020] [Indexed: 12/17/2022] Open
Abstract
Distinct manifestations of sexual behavior are conceived as separate phenotypes. Each sexual phenotype is assumed to be associated with a characteristic brain. These notions have justified the phenotyping of heterosexual copulator males based upon their ejaculation's latencies (EL) or frequencies (i.e., cumulative ejaculation number; EN). For instance, men and male rats showing premature, normal or retarded ejaculation are assumed to be distinctive endophenotypes. This concept, nonetheless, contradicts past and recent evidence that supports that sexual behavior is highly variable within each sex, and that the brain sexual functional morphology represents an intricate sexual phenotypic mosaic. Hence, for ejaculatory male endophenotypes to be considered as a valid biological concept, it must show internal consistency at various levels of organization (including genetic architectures), after being challenged by intrinsic and/or extrinsic factors. We then judged the internal consistency of the presumed ejaculatory endophenotypes by assessing whether copulatory behavior and the expression of copulation relevant genes and brain limbic structures are specific to each of the presumed EL- or EN-ejaculatory endophenotypes. To do this, copulating male rats were first phenotyped in groups consistently displaying short, average or long ejaculation latencies or very high, high, average, low or very low EN, based in their copulatory performance. Then, the internal consistency of the presumed EL- or EN-endophenotypes was tested by introducing as covariates of phenotyping other copulatory parameters (e.g., number of intromissions) in addition to EL or EN, or by analyzing the expression levels of genes encoding for estrogen receptor alpha, progesterone receptor, androgen receptor, aromatase, DNA methyl-transferase 3a and DNA methyl-transferase 1 in the amygdala, medial preoptic area, ventromedial hypothalamus and olfactory bulb. We found that even though there were group-level differences in all the variables that were studied, these differences did not add-up to create the presumed EL- or EN-ejaculatory endophenotypes. In fact, the extensive overlapping of copulatory parameters and expression levels of copulation relevant genes in limbic structures across EL- or EN-phenotyped copulating male rats, is not consistent with the hypothesis that distinct ejaculatory endophenotypes exist and that they are associated with specific brain characteristics.
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Affiliation(s)
- Itztli Trejo-Sánchez
- Laboratorio de Biología de Sistemas, Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Programa de Doctorado en Ciencias Biomédicas, Unidad de Posgrado, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Pérez-Monter
- Departamento de Gastroenterología, Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán”, Mexico City, Mexico
| | - Sofía Huerta-Pacheco
- Consejo Nacional de Ciencia y Tecnología, Ciencia Forense, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gabriel Gutiérrez-Ospina
- Laboratorio de Biología de Sistemas, Instituto de Investigaciones Biomédicas, Departamento de Biología Celular y Fisiología, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Coordinación de Psicobiología y Neurociencias, Facultad de Psicología, Universidad Nacional Autónoma de México, Mexico City, Mexico
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De Moura AC, Brito VB, Porawski M, Saffi J, Giovenardi M. Low maternal care is associated with increased oxidative stress in the brain of lactating rats. Brain Res 2017; 1655:17-22. [PMID: 27840190 DOI: 10.1016/j.brainres.2016.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 11/04/2016] [Accepted: 11/08/2016] [Indexed: 01/24/2023]
Abstract
Maternal care is crucial for offspring development and licking/grooming patterns can be induced by sensorial, neuroendocrine, and metabolic variations in the CNS. Important brain functions, such as learning and memory, can be influenced by oxidative stress, which can also modulate pathophysiological processes (e.g., depression, anxiety, and other psychiatric disorders). This study evaluated oxidative stress in the hippocampus (HP), olfactory bulb (OB), and plasma in Low-Licking (LL) and High-Licking (HL) lactating rats through superoxide dismutase (SOD) and catalase (CAT) activities, DNA damage (comet assay), and dihydrodichlorofluorescein (DCF) oxidation assay. Results demonstrate that in the HP of LL, the activities of SOD and CAT were increased compared to HL. In the OB, the activities of SOD and CAT were also increased in LL. The comet assay in the HP showed that LL had higher levels of basal damage and increased levels of DNA breaks than HL. In the OB, LL also had higher levels of DNA damage. In the plasma, no difference was observed in either SOD or CAT activities, but the DCF oxidation assay revealed that LL had higher levels of ROS production than HL. In conclusion, we observed that LL mothers showed evidence of increased oxidative stress when compared to HL, suggesting that variations in maternal behavior might be related to these biochemical parameters.
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Affiliation(s)
- Ana Carolina De Moura
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Verônica Bidinotto Brito
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Marilene Porawski
- Programa de Pós-Graduação em Biociências, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Jenifer Saffi
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil; Programa de Pós-Graduação em Biociências, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Márcia Giovenardi
- Programa de Pós-Graduação em Ciências da Saúde, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil; Programa de Pós-Graduação em Biociências, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre, Brazil.
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de Moura AC, da Silva IRV, Reinaldo G, Dani C, Elsner VR, Giovenardi M. Global Histone H4 Acetylation in the Olfactory Bulb of Lactating Rats with Different Patterns of Maternal Behavior. Cell Mol Neurobiol 2015; 36:1209-13. [DOI: 10.1007/s10571-015-0306-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 11/17/2015] [Indexed: 12/26/2022]
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de Moura AC, Lazzari VM, Becker RO, Gil MS, Ruthschilling CA, Agnes G, Almeida S, da Veiga ABG, Lucion AB, Giovenardi M. Gene expression in the CNS of lactating rats with different patterns of maternal behavior. Neurosci Res 2015; 99:8-15. [DOI: 10.1016/j.neures.2015.05.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 05/08/2015] [Accepted: 05/11/2015] [Indexed: 11/26/2022]
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Brumley MR, Kauer SD, Swann HE. Developmental plasticity of coordinated action patterns in the perinatal rat. Dev Psychobiol 2015; 57:409-20. [PMID: 25739742 DOI: 10.1002/dev.21280] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 12/10/2014] [Indexed: 11/08/2022]
Abstract
Some of the most simple, stereotyped, reflexive, and spinal-mediated motor behaviors expressed by animals display a level of flexibility and plasticity that is not always recognized. We discuss several examples of how coordinated action patterns have been shown to be flexible and adaptive in response to sensory feedback. We focus on interlimb and intralimb coordination during the expression of two action patterns (stepping and the leg extension response) in newborn rats, as well as interlimb motor learning. We also discuss the idea that the spinal cord is a major site for supporting plasticity in the developing motor system. An implication of this research is that normally occurring sensory stimulation during the perinatal period influences the typical development and expression of action patterns, and that exploiting the developmental plasticity of the motor system may lead to improved strategies for promoting recovery of function in human infants with motor disorders.
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Affiliation(s)
- Michele R Brumley
- Department of Psychology, Idaho State University, 921 S 8th Ave, Stop 8112, Pocatello, 83209-8112, ID
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Vargas-Martínez F, Uvnäs-Moberg K, Petersson M, Olausson HA, Jiménez-Estrada I. Neuropeptides as neuroprotective agents: Oxytocin a forefront developmental player in the mammalian brain. Prog Neurobiol 2014; 123:37-78. [DOI: 10.1016/j.pneurobio.2014.10.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 10/06/2014] [Indexed: 02/07/2023]
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Belnap SC, Allmond JT, Boomhower SR, Roberto ME, Brumley MR. Sensorimotor training during expression of the leg extension response (LER) in 1-day-old rats. Dev Psychobiol 2014; 56:1553-63. [PMID: 25171018 DOI: 10.1002/dev.21250] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 07/25/2014] [Indexed: 11/05/2022]
Abstract
In newborn rats, the leg extension response (LER) is a coordinated hyperextension of the hindlimbs that is shown in response to anogenital stimulation. Here we examined the influence of sensorimotor training on LER expression in postnatal day 1 rats. In Experiment 1, we examined if proprioceptive feedback facilitates LER expression. We did this by repeatedly stimulating the pup's anogenital region with a vibrotactile device, to experimentally evoke the LER, thus increasing LER-relevant hindlimb proprioceptive feedback during training. In trained subjects, the LER was evoked every 4 min for 15 trials, followed by a final LER test. Results indicated that proprioceptive feedback on its own did not alter later expression of the LER. In Experiment 2, we examined the effect of both proprioceptive and cutaneous feedback on LER expression, through the use of a range of motion (ROM) restriction during training. During ROM restriction, a Plexiglas plate was placed beneath the pup at 50% of limb length. After the 15th training trial, a final LER test occurred with no ROM restriction in place. Compared to controls, pups that experienced ROM restriction exhibited a significantly shorter LER duration, and smaller hip and ankle angles during the LER test (indicating greater limb flexion). Together these findings show that concurrent proprioceptive and cutaneous feedback, but not proprioceptive feedback alone, has persistent effects on expression of this newborn action pattern.
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Affiliation(s)
- Starlie C Belnap
- Department of Psychology, Idaho State University, 921 S 8th Ave, Stop 8112, Pocatello, ID, 83209-8112
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Turning sex inside-out: Peripheral contributions to sexual differentiation of the central nervous system. Biol Sex Differ 2012; 3:12. [PMID: 22640590 PMCID: PMC3464926 DOI: 10.1186/2042-6410-3-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 05/28/2012] [Indexed: 02/04/2023] Open
Abstract
Sexual differentiation of the nervous system occurs via the interplay of genetics, endocrinology and social experience through development. Much of the research into mechanisms of sexual differentiation has been driven by an implicit theoretical framework in which these causal factors act primarily and directly on sexually dimorphic neural populations within the central nervous system. This review will examine an alternative explanation by describing what is known about the role of peripheral structures and mechanisms (both neural and non-neural) in producing sex differences in the central nervous system. The focus of the review will be on experimental evidence obtained from studies of androgenic masculinization of the spinal nucleus of the bulbocavernosus, but other systems will also be considered.
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Analysis of transcriptional levels of the oxytocin receptor in different areas of the central nervous system and behaviors in high and low licking rats. Behav Brain Res 2012; 228:176-84. [DOI: 10.1016/j.bbr.2011.12.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 11/29/2011] [Accepted: 12/02/2011] [Indexed: 11/21/2022]
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Beery AK, Francis DD. Adaptive significance of natural variations in maternal care in rats: a translational perspective. Neurosci Biobehav Rev 2011; 35:1552-61. [PMID: 21458485 PMCID: PMC3104121 DOI: 10.1016/j.neubiorev.2011.03.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 03/12/2011] [Accepted: 03/22/2011] [Indexed: 01/31/2023]
Abstract
A wealth of data from the last fifty years documents the potency of early life experiences including maternal care on developing offspring. A majority of this research has focused on the developing stress axis and stress-sensitive behaviors in hopes of identifying factors impacting resilience and risk-sensitivity. The power of early life experience to shape later development is profound and has the potential to increase fitness of individuals for their environments. Current findings in a rat maternal care paradigm highlight the complex and dynamic relation between early experiences and a variety of outcomes. In this review we propose adaptive hypotheses for alternate maternal strategies and resulting offspring phenotypes, and suggest means of distinguishing between these hypotheses. We also provide evidence underscoring the critical role of context in interpreting the adaptive significance of early experiences. If our goal is to identify risk-factors relevant to humans, we must better explore the role of the social and physical environment in our basic animal models.
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Affiliation(s)
- Annaliese K Beery
- Robert Wood Johnson Foundation Health & Society Scholars Program, UCSF/UC Berkeley, San Francisco, CA, United States.
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Walker CD. Maternal touch and feed as critical regulators of behavioral and stress responses in the offspring. Dev Psychobiol 2010; 52:638-50. [DOI: 10.1002/dev.20492] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Lenz KM, Sengelaub DR. Maternal care effects on the development of a sexually dimorphic motor system: the role of spinal oxytocin. Horm Behav 2010; 58:575-81. [PMID: 20688065 PMCID: PMC2934889 DOI: 10.1016/j.yhbeh.2010.07.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2010] [Revised: 07/09/2010] [Accepted: 07/25/2010] [Indexed: 11/28/2022]
Abstract
Maternal licking in rats affects the development of the spinal nucleus of the bulbocavernosus (SNB), a sexually dimorphic motor nucleus that controls penile reflexes involved with copulation. Reduced maternal licking results in decreased motoneuron number, size, and dendritic length in the adult SNB, as well as deficits in adult male copulatory behavior. Our previous findings that licking-like tactile stimulation influences SNB dendritic development and upregulates Fos expression in the lumbosacral spinal cord suggest that afferent signaling is changed by differences in maternal stimulation. Oxytocin afferents from the hypothalamus are a possible candidate, given previous research that has shown oxytocin is released following sensory stimulation, oxytocin modulates excitability in the spinal cord, and is a pro-erectile modulator of male sex behavior. In this experiment, we used immunofluorescence and immediate early gene analysis to assess whether licking-like tactile stimulation of the perineum activated parvocellular oxytocinergic neurons in the hypothalamus in neonates. We also used enzyme immunoassay to determine whether this same stroking stimulation produced an increase in spinal oxytocin levels. We found that stroking increased Fos immunolabeling in small oxytocin-positive cells in the paraventricular nucleus of the hypothalamus, in comparison to unstroked or handled control pups. In addition, 60s of licking-like perineal stimulation produced a transient 89% increase in oxytocin levels in the lumbosacral spinal cord. Together, these results suggest that oxytocin afferent activity may contribute to the effects of early maternal care on the masculinization of the SNB and resultant male copulatory behavior.
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Affiliation(s)
- Kathryn M Lenz
- Department of Physiology and Program in Neuroscience, University of Maryland-Baltimore, MD 21201, USA.
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