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Acute effect of cholecystokinin on short-term synaptic plasticity in the rat hippocampus.

Dolatabadi LK, Reisi P - Res Pharm Sci (2014 Sep-Oct)

Bottom Line: Cholecystokinin (CCK), a peptide hormone found in the gut, is the most abundant peptide neurotransmitters in the brain, and its acute effects on the brain activity have been shown.The results showed that CCK-8S has a transient excitatory effects on baseline responses, but it inhibits paired pulse indices in acute.Therefore, in a short period of time, effect of CCK on the function of synapses is time dependent, and it has stimulatory or inhibitory effects at different time periods.

View Article: PubMed Central - PubMed

Affiliation: Applied Physiology Research Center, Isfahan University of Medical Sciences, Isfahan, I.R. Iran.

ABSTRACT
Cholecystokinin (CCK), a peptide hormone found in the gut, is the most abundant peptide neurotransmitters in the brain, and its acute effects on the brain activity have been shown. In this study we aimed to evaluate the acute effects of CCK on short-term synaptic plasticity in the dentate gyrus (DG) of the rat hippocampus. Via stereotaxic surgery, the stimulating and the recording electrodes were placed in the perforant pathway and dentate gyrus, respectively and 30 min after intraperitoneal (i.p.) injection of CCK octapeptide sulfated (CCK-8S, 1.6 μg/kg), evoked responses were recorded after delivering of paired-pulse stimulations at 10 to 500 ms inter-stimulus intervals. With respect to the control group that received saline instead of CCK, in baseline responses, slope of field excitatory postsynaptic potential (fEPSP) 5 min and 10 min after injection of CCK-8S (p<0.05) and population spikes (PS)- amplitudes 5 min after injection of CCK-8S (p<0.05) were significantly increased. In paired pulse responses, PS amplitudes were increased in the CCK group, but these enhancements only were significant at inter-stimulus interval 40 ms (p<0.05). However fEPSP slopes were decreased at inter-stimulus intervals 70 ms (p<0.05), 120 ms (p<0.01), 150 ms (p<0.001) and 300 ms (p<0.001). The results showed that CCK-8S has a transient excitatory effects on baseline responses, but it inhibits paired pulse indices in acute. Therefore, in a short period of time, effect of CCK on the function of synapses is time dependent, and it has stimulatory or inhibitory effects at different time periods.

No MeSH data available.


Schematic diagram of population spike and field excitatory postsynaptic potential analysis. The population spike parameters analyzed as: [the difference in voltage between the peak of the first positive wave and the peak of the first negative deflection (VB−VC) + the difference in voltage between the peak of the second positive wave and the peak of the first negative deflection (VD−VC)]/2 or [(VB-VC) + (VD-VC)]/2, and the field excitatory postsynaptic potential slope was measured as the slope between the baseline and the peak of the first positive wave (AB slope).
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Figure 1: Schematic diagram of population spike and field excitatory postsynaptic potential analysis. The population spike parameters analyzed as: [the difference in voltage between the peak of the first positive wave and the peak of the first negative deflection (VB−VC) + the difference in voltage between the peak of the second positive wave and the peak of the first negative deflection (VD−VC)]/2 or [(VB-VC) + (VD-VC)]/2, and the field excitatory postsynaptic potential slope was measured as the slope between the baseline and the peak of the first positive wave (AB slope).

Mentions: Stimulus–response or input/output (I/O) functions were acquired by systematic variation of the stimulus current (100–1000 μA) in order to evaluate synaptic potency before induction of paired pulse. Stimulus pulses were delivered at 0.1 Hz and five responses at each current level were averaged. As shown in Fig. 1, the population spike (PS) amplitude was measured using following equation:


Acute effect of cholecystokinin on short-term synaptic plasticity in the rat hippocampus.

Dolatabadi LK, Reisi P - Res Pharm Sci (2014 Sep-Oct)

Schematic diagram of population spike and field excitatory postsynaptic potential analysis. The population spike parameters analyzed as: [the difference in voltage between the peak of the first positive wave and the peak of the first negative deflection (VB−VC) + the difference in voltage between the peak of the second positive wave and the peak of the first negative deflection (VD−VC)]/2 or [(VB-VC) + (VD-VC)]/2, and the field excitatory postsynaptic potential slope was measured as the slope between the baseline and the peak of the first positive wave (AB slope).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4318001&req=5

Figure 1: Schematic diagram of population spike and field excitatory postsynaptic potential analysis. The population spike parameters analyzed as: [the difference in voltage between the peak of the first positive wave and the peak of the first negative deflection (VB−VC) + the difference in voltage between the peak of the second positive wave and the peak of the first negative deflection (VD−VC)]/2 or [(VB-VC) + (VD-VC)]/2, and the field excitatory postsynaptic potential slope was measured as the slope between the baseline and the peak of the first positive wave (AB slope).
Mentions: Stimulus–response or input/output (I/O) functions were acquired by systematic variation of the stimulus current (100–1000 μA) in order to evaluate synaptic potency before induction of paired pulse. Stimulus pulses were delivered at 0.1 Hz and five responses at each current level were averaged. As shown in Fig. 1, the population spike (PS) amplitude was measured using following equation:

Bottom Line: Cholecystokinin (CCK), a peptide hormone found in the gut, is the most abundant peptide neurotransmitters in the brain, and its acute effects on the brain activity have been shown.The results showed that CCK-8S has a transient excitatory effects on baseline responses, but it inhibits paired pulse indices in acute.Therefore, in a short period of time, effect of CCK on the function of synapses is time dependent, and it has stimulatory or inhibitory effects at different time periods.

View Article: PubMed Central - PubMed

Affiliation: Applied Physiology Research Center, Isfahan University of Medical Sciences, Isfahan, I.R. Iran.

ABSTRACT
Cholecystokinin (CCK), a peptide hormone found in the gut, is the most abundant peptide neurotransmitters in the brain, and its acute effects on the brain activity have been shown. In this study we aimed to evaluate the acute effects of CCK on short-term synaptic plasticity in the dentate gyrus (DG) of the rat hippocampus. Via stereotaxic surgery, the stimulating and the recording electrodes were placed in the perforant pathway and dentate gyrus, respectively and 30 min after intraperitoneal (i.p.) injection of CCK octapeptide sulfated (CCK-8S, 1.6 μg/kg), evoked responses were recorded after delivering of paired-pulse stimulations at 10 to 500 ms inter-stimulus intervals. With respect to the control group that received saline instead of CCK, in baseline responses, slope of field excitatory postsynaptic potential (fEPSP) 5 min and 10 min after injection of CCK-8S (p<0.05) and population spikes (PS)- amplitudes 5 min after injection of CCK-8S (p<0.05) were significantly increased. In paired pulse responses, PS amplitudes were increased in the CCK group, but these enhancements only were significant at inter-stimulus interval 40 ms (p<0.05). However fEPSP slopes were decreased at inter-stimulus intervals 70 ms (p<0.05), 120 ms (p<0.01), 150 ms (p<0.001) and 300 ms (p<0.001). The results showed that CCK-8S has a transient excitatory effects on baseline responses, but it inhibits paired pulse indices in acute. Therefore, in a short period of time, effect of CCK on the function of synapses is time dependent, and it has stimulatory or inhibitory effects at different time periods.

No MeSH data available.