This study investigated the effects of alcohol on neurogenesis and memory in rats. Rats were injected with alcohol (2g/kg) or served as controls for 3 days. Those given alcohol showed increased A-type potassium currents in hippocampal granule cells, decreased proliferation of these cells, and impaired memory compared to controls. Patch clamp recordings revealed that alcohol increased the amplitude and frequency of potassium currents. Immunohistochemistry labeling for proliferating cell nuclear antigen also demonstrated reduced proliferation of granule cells. The authors concluded that increased potassium currents induced by alcohol may decrease signals for cell proliferation in the hippocampus and impair memory formation in adult rats.

1. Faisal Khan and Kaneez Fatima Shad
Dr. Panjwani Center for Molecular Medicine and Drug Research, ICCBS, University of Karachi
Results
MATERIAL AND METHODS
ABSTRACT
New neurons are formed continuously throughout life in mammalian dentate gyrus region of
hippocampus that contains neuronal precursor cells. These new cells are partially responsible in
the generation of new memory. Many factors (such as alcohol) results in a dramatic decrease in
cell proliferation in the dentate subgranular zone (SGZ) and impaired memory.
We have investigated the role of A-type K currents during alcohol induced decrease in
neurogenesis and memory impairment. Adult Sprague-Dawley rats weighing 150±10 g were
used for the experiments after getting the animal ethic approval from PCMD, University of
Karachi. Animals were divided into 2 groups: the control group and the alcohol-treated group.
Animals of the alcohol-treated groups were injected intraperitoneally with alcohol (2 g/kg) once a
day for 3 days. Treatment with alcohol for 3 days inhibited cell proliferation. Animals were
scarified right after testing their memory in T-maze. Slices (40µm) of hippocampus were labeled
with proliferating cell nuclear antigen (PCNA) as to observe and compare the extent of the cell
proliferation in alcohol treated group with that of control. Patch clamp technique was used in
whole cell configuration mode to observe A type K+
currents in the granule cells of each group.
Our initial observations indicated that alcohol increases the amplitude and frequency of A-type K+
currents and decreases the proliferation (neurogenesis) of granule cells in hippocampus and
impaired the memory. We concluded that increase in A type K+
currents may results in decrease
signals for cell proliferation in dentate subgranular zone and impaired memory in adult rats.
INTRODUCTION
Effect of alcohol on A-type K+
currents induced neurogenesis and resultant
memory impairment in adult rats
Alcohol Treatment
Animals were injected with alcohal 2g/kg. Once per day for 3 days and were sacrified 2 hours after last
injection
Patch Clamp recordings
Cells continuously perfused with ACSF containing (in mM): 140 NaCl, 5.6
KCl, 10 HEPES, 2 CaCl2, 2 MgCl2, 10 glucose, and pH 7.3, and osmolarity
adjusted to 325±5 mOsml. Patch electrodes with a resistance of 3 to 5 MΩ were
pulled on a Brown-Flaming P-97 electrode puller, fire-polished and filled with
a solution containing (in mM): 145 KCl, 10 EGTA, 2 MgCl2, 2 CaCl2 and 5
HEPES, pH 7.2, osmolarity adjusted to 290±10mOsm. Patch clamp recordings
were carried out using an HEKA amplifier.
This research was supported by a grant from Higher Education Commission, Pakistan.
For further information
Please contact; ftmshad@gmail.com.
faisraza@yahoo.com, faisal_khan@iccs.edu.pk,
Electrophysiology Lab, Dr. Punjwani Center for
Molecular Medicine and Drug Research,
University of Karachi, Karachi, Pakistan.
Memory Test
Each rat was trained for 5 days to run to the ends of the arms for a
food reward During the first day, food was liberally spread
throughout the maze; each rat was allowed 20 min to explore. During
each successive day, the amount of food was progressively restricted
so that, by the fifth day, food was present only in the food cups. The
rats were given no food in their home cages.
Immunohistochemistry
Animals deeply anaesthetized with ketamine and transcardially perfused with 0.1 m phosphate-buffered
saline (PBS, pH 7.4) followed by 4% paraformaldehyde in PBS. The brains were then cut 40-µm thick
by cryostate.
The tissue was incubated with anti-mouse PCNA (1:250, DAKO) overnight at 4o
C following washes in
TBS, sections were incubated in the dark for 1 h in fluorescent-coupled secondary antibodies (goat anti-
mouse texas red) plus 1.5% goat serum. After sections were mounted and dried, they were coverslipped
with mounting medium.
Drink Alcohol Less neuronal stimulation
Decrease neuron generation
Less neuronal integration
Problems in memory and leaning
Normal Potassium Currents
Effect of alcohol on
Potassium Currents
Control Alcoholic rats showing less neurogenesis
Conclusion
Alcohol increase the
potassium current amplitude
Increased potassium
currents may responsible to
reduce proliferation of
neural stem cells.
Decrease proliferation
disturb the ability to learn
and impair the memory.
Effect of alcohol on proliferation