Limits...
Time-dependent expression of Arc and zif268 after acquisition of fear conditioning.

Lonergan ME, Gafford GM, Jarome TJ, Helmstetter FJ - Neural Plast. (2010)

Bottom Line: Arc, an effector immediate early gene, and zif268, a regulatory transcription factor, have been implicated in synaptic plasticity underlying learning and memory.The timing of hippocampal Arc and zif268 expression coincides with the critical period for protein synthesis-dependent memory consolidation following fear conditioning.These findings suggest that altered Arc and zif268 expression are related to neural plasticity during the formation of fear memory.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Wisconsin-Milwaukee, 2441 E. Hartford Avenue, Milwaukee, WI 53211, USA.

ABSTRACT
Memory consolidation requires transcription and translation of new protein. Arc, an effector immediate early gene, and zif268, a regulatory transcription factor, have been implicated in synaptic plasticity underlying learning and memory. This study explored the temporal expression profiles of these proteins in the rat hippocampus following fear conditioning. We observed a time-dependent increase of Arc protein in the dorsal hippocampus 30-to-90-minute post training, returning to basal levels at 4 h. Zif268 protein levels, however, gradually increased at 30-minute post training before peaking in expression at 60 minute. The timing of hippocampal Arc and zif268 expression coincides with the critical period for protein synthesis-dependent memory consolidation following fear conditioning. However, the expression of Arc protein appears to be driven by context exploration, whereas, zif268 expression may be more specifically related to associative learning. These findings suggest that altered Arc and zif268 expression are related to neural plasticity during the formation of fear memory.

Show MeSH

Related in: MedlinePlus

Expression of Arc protein in the dorsal hippocampus following fear conditioning.  (a) The temporal expression profile for Arc protein shows a noticeable increase in expression at 30 min, continuing through 90 min post training.  The rise in Arc protein diminishes over time, reaching basal levels by 4 hr post training.  Bar graph represents the group means ± SEM.  Representative western blot images are presented for each group directly below the corresponding graph plot.  Significant differences from home cage (HC) controls are denoted with asterisks: *P < .05, **P < .01. (b) Brightfield photomicrograph (2× magnification) of the dorsal hippocampus.  The boxed area indicates the region depicted in the immunofluorescence images of C and D (10× magnification).  (c) Basal expression of Arc protein in the dentate gyrus is low in the home cage control animal.  (d) Arc protein expression is significantly increased in granule cells of the dentate gyrus 90 min after fear conditioning.  (e, f) Higher magnification photomicrographs (20× magnification) of the boxed regions from (c) and (d), respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC2877205&req=5

fig2: Expression of Arc protein in the dorsal hippocampus following fear conditioning. (a) The temporal expression profile for Arc protein shows a noticeable increase in expression at 30 min, continuing through 90 min post training. The rise in Arc protein diminishes over time, reaching basal levels by 4 hr post training. Bar graph represents the group means ± SEM. Representative western blot images are presented for each group directly below the corresponding graph plot. Significant differences from home cage (HC) controls are denoted with asterisks: *P < .05, **P < .01. (b) Brightfield photomicrograph (2× magnification) of the dorsal hippocampus. The boxed area indicates the region depicted in the immunofluorescence images of C and D (10× magnification). (c) Basal expression of Arc protein in the dentate gyrus is low in the home cage control animal. (d) Arc protein expression is significantly increased in granule cells of the dentate gyrus 90 min after fear conditioning. (e, f) Higher magnification photomicrographs (20× magnification) of the boxed regions from (c) and (d), respectively.

Mentions: We found that induction of Arc protein expression for trained rats was monophasic in the dorsal hippocampus, with a significant increase detected between 30 min and 90 min post training before returning to near basal levels at 4 hr (Figure 2(a)). A one-way ANOVA revealed that the level of Arc protein expression was time-dependent following fear conditioning (F(7,79) = 4.265, P < .001). LSD post hoc comparisons showed that when compared to untrained HC animals, Arc protein was significantly increased in trained rats at 30 min (MD = 34.4587, P < .01), 60 min (MD = 58.0035, P < .001), and 90 min (MD = 50.8044, P < .01).


Time-dependent expression of Arc and zif268 after acquisition of fear conditioning.

Lonergan ME, Gafford GM, Jarome TJ, Helmstetter FJ - Neural Plast. (2010)

Expression of Arc protein in the dorsal hippocampus following fear conditioning.  (a) The temporal expression profile for Arc protein shows a noticeable increase in expression at 30 min, continuing through 90 min post training.  The rise in Arc protein diminishes over time, reaching basal levels by 4 hr post training.  Bar graph represents the group means ± SEM.  Representative western blot images are presented for each group directly below the corresponding graph plot.  Significant differences from home cage (HC) controls are denoted with asterisks: *P < .05, **P < .01. (b) Brightfield photomicrograph (2× magnification) of the dorsal hippocampus.  The boxed area indicates the region depicted in the immunofluorescence images of C and D (10× magnification).  (c) Basal expression of Arc protein in the dentate gyrus is low in the home cage control animal.  (d) Arc protein expression is significantly increased in granule cells of the dentate gyrus 90 min after fear conditioning.  (e, f) Higher magnification photomicrographs (20× magnification) of the boxed regions from (c) and (d), respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2877205&req=5

fig2: Expression of Arc protein in the dorsal hippocampus following fear conditioning. (a) The temporal expression profile for Arc protein shows a noticeable increase in expression at 30 min, continuing through 90 min post training. The rise in Arc protein diminishes over time, reaching basal levels by 4 hr post training. Bar graph represents the group means ± SEM. Representative western blot images are presented for each group directly below the corresponding graph plot. Significant differences from home cage (HC) controls are denoted with asterisks: *P < .05, **P < .01. (b) Brightfield photomicrograph (2× magnification) of the dorsal hippocampus. The boxed area indicates the region depicted in the immunofluorescence images of C and D (10× magnification). (c) Basal expression of Arc protein in the dentate gyrus is low in the home cage control animal. (d) Arc protein expression is significantly increased in granule cells of the dentate gyrus 90 min after fear conditioning. (e, f) Higher magnification photomicrographs (20× magnification) of the boxed regions from (c) and (d), respectively.
Mentions: We found that induction of Arc protein expression for trained rats was monophasic in the dorsal hippocampus, with a significant increase detected between 30 min and 90 min post training before returning to near basal levels at 4 hr (Figure 2(a)). A one-way ANOVA revealed that the level of Arc protein expression was time-dependent following fear conditioning (F(7,79) = 4.265, P < .001). LSD post hoc comparisons showed that when compared to untrained HC animals, Arc protein was significantly increased in trained rats at 30 min (MD = 34.4587, P < .01), 60 min (MD = 58.0035, P < .001), and 90 min (MD = 50.8044, P < .01).

Bottom Line: Arc, an effector immediate early gene, and zif268, a regulatory transcription factor, have been implicated in synaptic plasticity underlying learning and memory.The timing of hippocampal Arc and zif268 expression coincides with the critical period for protein synthesis-dependent memory consolidation following fear conditioning.These findings suggest that altered Arc and zif268 expression are related to neural plasticity during the formation of fear memory.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of Wisconsin-Milwaukee, 2441 E. Hartford Avenue, Milwaukee, WI 53211, USA.

ABSTRACT
Memory consolidation requires transcription and translation of new protein. Arc, an effector immediate early gene, and zif268, a regulatory transcription factor, have been implicated in synaptic plasticity underlying learning and memory. This study explored the temporal expression profiles of these proteins in the rat hippocampus following fear conditioning. We observed a time-dependent increase of Arc protein in the dorsal hippocampus 30-to-90-minute post training, returning to basal levels at 4 h. Zif268 protein levels, however, gradually increased at 30-minute post training before peaking in expression at 60 minute. The timing of hippocampal Arc and zif268 expression coincides with the critical period for protein synthesis-dependent memory consolidation following fear conditioning. However, the expression of Arc protein appears to be driven by context exploration, whereas, zif268 expression may be more specifically related to associative learning. These findings suggest that altered Arc and zif268 expression are related to neural plasticity during the formation of fear memory.

Show MeSH
Related in: MedlinePlus