Tactile stimulation during different developmental periods modifies hippocampal BDNF and GR, affecting memory and behavior in adult rats

Abstract

Recent studies have shown that tactile stimulation (TS) in pups is able to prevent and/or minimize fear, anxiety behaviors, and addiction to psychostimulant drugs in adult rats. In these studies, animals have been exposed to handling from postnatal day (PND) 1-21. This study was designed to precisely establish which period of preweaning development has a greater influence of TS on neuronal development. After birth, male pups were exposed to TS from PND1-7, PND8-14, and PND15-21. In adulthood, the different periods of postnatal TS were assessed through behavioral, biochemical, and molecular assessments. Animals that received TS from PND8-14 showed lower anxiety-like symptoms, as observed by decreased anxiety index in elevated plus maze. This same TS period was able to improve rats' working memory by increasing the percentage of alternation rate in Y-maze, and induce better ability to cope with stressful situations, as showed in the defensive burying test by a reduced time of burying behavior. On the other hand, animals receiving TS in the first week of life showed longest cumulative burying time, which is directly related to increased anxiety-like behavior. Moreover, TS from PND8-14 showed lower corticosterone levels and better oxidative status, as observed by decreased lipid peroxidation and increased catalase activity in the hippocampus. Brain-derived neurotrophic factor (BDNF) immunocontent was increased in the hippocampus of animals receiving TS from PND8-14, while glucocorticoid receptors immunocontent was decreased in both TS and TS , but not TS . To the best of our knowledge, this study is the first to show TS can be more efficient if applied over a focused period of neonatal development (PND8-14) and this beneficial influence can be reflected on reduced emotionality and increased ability to address stressful situations in adulthood. © 2016 Wiley Periodicals, Inc.

Early postnatal development of electrophysiological and histological properties of sensory sural nerves in male rats that were maternally deprived and artificially reared: Role of tactile stimulation

“…Our results coincide with a large body of work showing that early negative (complete maternal deprivation, early weaning or undernourishment), or positive (tactile and social stimulation) experiences modify myelination and the electrophysiological function of the CNS (Chatterjee et al, ; Kikusui et al, ; Ono et al, ; Horiquini‐Barbosa and Lachat, ; Antoniazzi et al, ) and the PNS (Segura et al, ; Segura et al, ; Quiroz‐González et al, ). Moreover, our results allow us to propose a discrete window of developmental time (PNDs 7–14), during which tactile stimulation normally exerts positive effects on myelination (Kikusui et al, ; Ono et al, ).…”

“…These alterations were prevented by the replacement of tactile stimulation during isolation (Chatterjee et al, 2007). Similarly, tactile stimulation across PNDs 8-14 increased BDNF expression in the hippocampus (Antoniazzi et al, 2017), and increased IGF-1 expression in the cortex when delivered across PNDs 1-12 (Guzzetta et al, 2009). Thus, in the AR rat model, tactile stimulation might have promoted the expression of trophic factors that support myelination of the SU nerve.…”

Neonatal Tactile Stimulation Alters Behaviors in Heterozygous Serotonin Transporter Male Rats: Role of the Amygdala

“…Not only the total Bdnf but also alterations in Bdnf isoform VI and IV were related to increased anxiety in male rats after acute stress exposure (Luoni et al, 2016;Pandey et al, 2017). Although a previous study demonstrated that TS in Wistar rats led to an increase in Bdnf levels in the hippocampus, along with a beneficial effect on anxiety and an improvement in working memory as evaluated using the Y-maze test (Antoniazzi et al, 2017), in our study the decrease of Bdnf expression in the basolateral amygdala in TS animals could be indicative of a protective mechanism against anxiety and anhedonic behaviors.…”

Gentle Handling Attenuates Innate Defensive Responses to Visual Threats

“…Tactile stimuli is a fundamental form of sensory perception conserved across species ( Ratcliffe, 2012 ). Gentle handling has been shown to reduce stress, modify cognitive behavior, and improve the relationship between handlers and animals ( Harlow and Suomi, 1970 ; Antoniazzi et al, 2017 ). Furthermore, gentle handling has been proven to decrease depression and reduce anxiety-like behavior in laboratory mice ( Grandin, 1997 ; Madruga et al, 2006 ).…”