Measuring Behavior in the Home Cage : Study Design, Applications, Challenges, and Perspectives

FUNDING This research was supported by NIH grants R00AG056662, P20GM125528, AG057424 to WS and SLPeer reviewedPublisher PD

The cardiac effects of carbon nanotubes in rat

Introduction: Carbon nanotubes (CNTs) are novel candidates in nanotechnology with a variety of increasing applications in medicine and biology. Therefore the investigation of nanomaterials’ biocompatibility can be an important topic. The aim of present study was to investigate the CNTs impact on cardiac heart rate among rats. Methods: Electrocardiogram (ECG) signals were recorded before and after injection of CNTs on a group with six rats. The heart rate variability (HRV) analysis was used for signals analysis. The rhythm-to-rhythm (RR) intervals in HRV method were computed and features of signals in time and frequency domains were extracted before and after injection. Results: Results of the HRV analysis showed that CNTs increased the heart rate but generally these nanomaterials did not cause serious problem in autonomic nervous system (ANS) normal activities. Conclusion: Injection of CNTs in rats resulted in increase of heart rate. The reason of phenomenon is that multiwall CNTs may block potassium channels. The suppressed and inhibited IK and potassium channels lead to increase of heart rate

Ultrahigh-resolution MRI reveals structural brain differences in serotonin transporter knockout rats after sucrose and cocaine self-administration

Excessive use of cocaine is known to induce changes in brain white and gray matter. It is unknown whether the extent of these changes is related to individual differences in vulnerability to cocaine addiction. One factor increasing vulnerability involves reduced expression of the serotonin transporter (5-HTT). Human studies have shown that inherited 5-HTT downregulation is associated with structural changes in the brain. These genotype-related structural changes may contribute to risk for cocaine addiction. Here, we tested this idea by using ultrahigh-resolution structural magnetic resonance imaging (MRI) on postmortem tissue of 5-HTT −/− and wild-type (5-HTT +/+ ) rats with a history of long access to cocaine or sucrose (control) self-administration. We found that 5-HTT −/− rats, compared with wild-type control animals, self-administered more cocaine, but not sucrose, under long-access conditions. Ultrahigh-resolution structural MRI subsequently revealed that, independent of sucrose or cocaine self-administration, 5-HTT −/− rats had a smaller amygdala. Moreover, we found an interaction between genotype and type of reward for dorsal raphe nucleus volume. The data point to an important but differential role of the amygdala and dorsal raphe nucleus in 5-HTT genotype–dependent vulnerability to cocaine addiction

Ultrahigh-resolution MRI reveals structural brain differences in serotonin transporter knockout rats after sucrose and cocaine self-administration

Excessive use of cocaine is known to induce changes in brain white and gray matter. It is unknown whether the extent of these changes is related to individual differences in vulnerability to cocaine addiction. One factor increasing vulnerability involves reduced expression of the serotonin transporter (5-HTT). Human studies have shown that inherited 5-HTT downregulation is associated with structural changes in the brain. These genotype-related structural changes may contribute to risk for cocaine addiction. Here, we tested this idea by using ultrahigh-resolution structural magnetic resonance imaging (MRI) on postmortem tissue of 5-HTT-/- and wild-type (5-HTT+/+ ) rats with a history of long access to cocaine or sucrose (control) self-administration. We found that 5-HTT-/- rats, compared with wild-type control animals, self-administered more cocaine, but not sucrose, under long-access conditions. Ultrahigh-resolution structural MRI subsequently revealed that, independent of sucrose or cocaine self-administration, 5-HTT-/- rats had a smaller amygdala. Moreover, we found an interaction between genotype and type of reward for dorsal raphe nucleus volume. The data point to an important but differential role of the amygdala and dorsal raphe nucleus in 5-HTT genotype-dependent vulnerability to cocaine addiction

Ultrahigh-resolution MRI reveals structural brain differences in serotonin transporter knockout rats after sucrose and cocaine self-administration

Excessive use of cocaine is known to induce changes in brain white and gray matter. It is unknown whether the extent of these changes is related to individual differences in vulnerability to cocaine addiction. One factor increasing vulnerability involves reduced expression of the serotonin transporter (5-HTT). Human studies have shown that inherited 5-HTT downregulation is associated with structural changes in the brain. These genotype-related structural changes may contribute to risk for cocaine addiction. Here, we tested this idea by using ultrahigh-resolution structural magnetic resonance imaging (MRI) on postmortem tissue of 5-HTT-/- and wild-type (5-HTT+/+ ) rats with a history of long access to cocaine or sucrose (control) self-administration. We found that 5-HTT-/- rats, compared with wild-type control animals, self-administered more cocaine, but not sucrose, under long-access conditions. Ultrahigh-resolution structural MRI subsequently revealed that, independent of sucrose or cocaine self-administration, 5-HTT-/- rats had a smaller amygdala. Moreover, we found an interaction between genotype and type of reward for dorsal raphe nucleus volume. The data point to an important but differential role of the amygdala and dorsal raphe nucleus in 5-HTT genotype-dependent vulnerability to cocaine addiction