Effects of Maternal Care on Spinal Cord Development and Reproductive Behavior in Male Rats Joy...
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Transcript of Effects of Maternal Care on Spinal Cord Development and Reproductive Behavior in Male Rats Joy...
![Page 1: Effects of Maternal Care on Spinal Cord Development and Reproductive Behavior in Male Rats Joy Garrett Katy Lenz Aaron Wilber.](https://reader036.fdocuments.in/reader036/viewer/2022062315/5697bf8a1a28abf838c8ad5a/html5/thumbnails/1.jpg)
Effects of Maternal Care on Spinal Cord Development and
Reproductive Behavior in Male Rats
Joy Garrett
Katy Lenz
Aaron Wilber
![Page 2: Effects of Maternal Care on Spinal Cord Development and Reproductive Behavior in Male Rats Joy Garrett Katy Lenz Aaron Wilber.](https://reader036.fdocuments.in/reader036/viewer/2022062315/5697bf8a1a28abf838c8ad5a/html5/thumbnails/2.jpg)
Maternal Licking Behavior
•During first 2 postnatal weeks
•Anogenital Licking
•Dams lick male pups more than female pups
•Important for brain development and behavior, including stress reactivity, emotionality, learning and memory, and sexual behavior
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Maternal licking influences adult male sex behavior
Reducing maternal licking produces deficits in male copulatory behavior:
• Longer latency to ejaculation
• Longer post-ejaculatory intromission latency
• Longer inter-intromission intervals
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Spinal Nucleus of the Bulbocavernosus (SNB)
• Sexually dimorphic
• Hormone sensitive
• Controls penile reflexes during copulation
• Development is activity-dependent
• Dendritic development is biphasic: outgrowth until P28 retraction from P28 until P49
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Maternal licking alters SNB motoneuron number
Graph from Moore et al. (1992)
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Adult dendritic length is affected by maternal licking
Control Reduced Licking
Adult dendritic length per motoneuron is regionally reduced by approximately 50% in the reduced licking offspring
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Control Reduced Licking
Seconds/Observation
0
20
40
60
80
100
120
140
*
Experimental Set-Up
•Zinc sulfate reduces maternal licking by reducing olfactory acuity
P1, 2, 3, 5, 8, 11, 14
ZINC SULFATE
SALINE
1)HRP injection: P28 or P492)Hormone Assay: P1, P7, or P143)Immunohistochemistry: P49 4)Gene Array: P49
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1. Neuroanatomy• Already know adult dendritic length is affected. We will also
look at an earlier developmental timepoint (P28) to see if dendritic outgrowth is affected versus dendritic retraction
• Horseradish peroxidase (HRP) retrograde labeling allows visualization of SNB motorneuron morphology
• Use Neurolucida to reconstruct dendritic arbor across the population of motoneurons
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2. Hormone Assay• Deprivation of maternal care is a stressor: causes
increases in both ACTH and CORT
• SNB motoneurons highly express glucocorticoid receptors (GR)
• Stress also suppresses the HPG axis production of testosterone (T), and SNB motoneuron dendrites depend on T
• Perform an EIA on the plasma of control and licking-deprived rat pups on days 1, 7, and 14, to look at T and CORT levels
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3. Immunohistochemistry• It is possible that licking-induced
changes in steroid hormone receptor expression could control the effects of licking on SNB dendritic morphology.
• Both GR and androgen receptors (AR) of receptors are expressed highly in the SNB
• On P49, perform immunohistochemistry on control and licking-deprived rats to look for differences in GR and AR expression
Photomicrograph taken from Blanco et al. (2003)
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4. Gene Array• Other molecular factors affect dendritic arborization of
SNB motoneurons (e.g. ciliary neurotrophic factor (CNTF) and brain derived neurotrophic factor (BDNF)). Many of these factors are target-derived.
• Perfrom a gene microarray on purified RNA of the SNB muscle tissue both during the maternal licking period and in adulthood (P49)
• This will demonstrate which genes are up- or down-regulated by maternal care