This document summarizes a study that evaluated the effect of moderate prenatal ethanol exposure on the expression of two histamine H3 receptor isoforms in the brains of adult rat offspring. The study used techniques like qRT-PCR to analyze gene expression levels, western blotting to detect protein concentrations, and in situ hybridization to locate nucleic acid sequences in brain tissues. Results are presented in figures 6 through 9. The discussion cites other studies and agrees that mRNA and protein expression levels do not always correlate and that histamine receptors can dimerize with other neurotransmitter receptors. The conclusions note that alcohol exposure in utero can cause neurological disabilities differently in females and males, and may indirectly affect histamine receptor function through other mechanisms.

1. Juliana Restrepo Sibaja
Semestre III, medicina
Universidad Pontificia Bolivariana

2. Histamine H3 receptors

3. Placenta - alcohol
levels
Prenatal ethanol exposure
Alcohol crosses the placenta,
which means the developing
fetus is exposed to the same
blood levels of alcohol as their
mother.
Because of liver development,
alcohol effect is more severe
for the fetus.
A range of lifelong adverse
developmental conditions caused
by in utero alcohol exposure.
FASD
Image taken from HealthyChildren.org

4. General objective
Evaluate the Effect of moderate prenatal ethanol
exposure on the differential expression of two
histamine H3 receptor isoforms in different brain
regions of adult rat offspring

5. In a PCR test a specific genetic material
sequence is amplified, in this case
we´re working with RNA in a
quantitative form, which shows us the
amount of gene expression per
sample.
This means that prenatal ethanol
exposure is being evaluated through
certain receptors.
Knockout mice are genetically
engineered mice in which a single
gene is manipulated. In this case,
they carry an altered copy of the
hrh3 gene with neomycin resistance.
This is important in this study,
because antibiotics like neomycin
prevent liver injury and decrease
ethanol levels on the subject.
Materials & methods
2.5. Breeding of H3R
knockout mice
2.6. RNA extraction and
qRT-PCR from mouse
frontal cortex

6. Western Blotting is a technique used to
separate and identify a specific protein
within a blood or tissue sample.
In this study this test is used to detect
protein concentrations in P2
membranes with different molecular
masses. For instance, there is emphasis
on H3RA antibody at ~48 kDa.
ISH studies make possible the
detection of a specific nucleic acid
sequence within a cell. Then the
sequence is bound in a tissue
section by complementary base
pairing with a probe.
In this investigation the probes were
designed to recognize rH3A and
rH3C mRNA.
Materials & methods
2.3. In situ hybridization
(ISH) studies 2.9.1. Western blotting

7. Results
Figure 6
Figure 7

8. Results
Figure 8 Figure 9

9. Discussion
Author What they said Agree / disagree
Moritz et al., 2019
“There are cases where there are either none or
even negative correlations between mRNA
expression and protein expression data.”
Agree
Varaschin et al., 2018
“Given the limitations of interpreting changes in
mRNA expression relative to measures of H3R
function, it was important to quantitate H3R
isoform protein expression in brain regions
where PAE altered H3R mRNA expression.”
Agree
Shenton et al., 2005;
Márquez-Gómez et al.,
2018
“Consistent with our observations of rH3A
mRNA-overexpressing HEK-293 cells (Figure
9B), a number of studies have reported that
H3Rs can dimerize with a variety of other
neurotransmitter receptors”
Agree

10. Conclusions
● Alcohol is a dangerous substance that can
cause various disabilities in utero, specially
neurologically wise.
● PAE is in some aspects sex related. For
example, alcohol exposure affects different
brain areas in female and male rats.
● Even if PAE doesn’t affect H3R expression
directly, it affects different mechanisms that
will end up modifying its function.