Corrigendum: Measuring Locomotor Activity and Behavioral Aspects of Rodents Living in the Home-Cage.

[This corrects the article DOI: 10.3389/fnbeh.2022.

Measuring Locomotor Activity and Behavioral Aspects of Rodents Living in the Home-Cage.

Automatization and technological advances have led to a larger number of methods and systems to monitor and measure locomotor activity and more specific behavior of a wide variety of animal species in various environmental conditions in laboratory settings. In rodents, the majority of these systems require the animals to be temporarily taken away from their home-cage into separate observation cage environments which requires manual handling and consequently evokes distress for the animal and may alter behavioral responses. An automated high-throughput approach can overcome this problem.

Functional deletion of neuropeptide Y receptors type 2 in local synaptic networks of anteroventral BNST facilitates recall and increases return of fear.

Return of previously extinguished fear memories presents a major hurdle in treatment of fear-related disorders. Neuropeptide Y receptors type 2 (Y2R) in the bed nucleus of stria terminalis (BNST) seem to play a crucial role in modulation of remote fear memories. Here, we targeted Cre-channelrhodopsin-2 to defined subregions of BNST or central amygdala (CeA) in floxed Y2R mice (Y2) for functional deletion of Y2R.

Single stimulation of Y2 receptors in BNSTav facilitates extinction and dampens reinstatement of fear.

Rationale: Return of fear by re-exposure to an aversive event is a major obstacle in the treatment of fear-related disorders. Recently, we demonstrated that local pharmacological stimulation of neuropeptide Y type 2 receptors (Y2R) in anteroventral bed nucleus of stria terminalis (BNSTav) facilitates fear extinction and attenuates retrieval of remote fear with or without concomitant extinction training. Whether Y2R activation could also protect against re-exposure to traumatic events is still unknown.

Hippocampal NPY Y2 receptors modulate memory depending on emotional valence and time.

Posttraumatic stress disorder is characterized by contextually inappropriate, dys-regulated and generalized fear expression and often resistant to therapy. The hippocampus integrates contextual information into spatial and emotional memories, but how diverse modulatory neurotransmitters are shaping this process is not known. Neuropeptide Y is a peptide-neurotransmitter, which modulates hippocampal excitability by activating several G-protein-coupled receptors.

Neuropeptide Y2 receptors in anteroventral BNST control remote fear memory depending on extinction training.

The anterior bed nucleus of stria terminalis (BNST) is involved in reinstatement of extinguished fear, and neuropeptide Y2 receptors influence local synaptic signaling. Therefore, we hypothesized that Y2 receptors in anteroventral BNST (BNSTav) interfere with remote fear memory and that previous fear extinction is an important variable. C57BL/6NCrl mice were fear-conditioned, and a Y2 receptor-specific agonist (NPY) or antagonist (JNJ-5207787) was applied in BNSTav before fear retrieval at the following day.

Hunger Promotes Fear Extinction by Activation of an Amygdala Microcircuit.

Emotions control evolutionarily-conserved behavior that is central to survival in a natural environment. Imbalance within emotional circuitries, however, may result in malfunction and manifestation of anxiety disorders. Thus, a better understanding of emotional processes and, in particular, the interaction of the networks involved is of considerable clinical relevance.

Differential expression of L- and N-type voltage-sensitive calcium channels in the spinal cord of morphine+nimodipine treated rats.

We have earlier reported that nifedipine and nimodipine, both L-type voltage-sensitive calcium channel (L-VSCC) antagonists, attenuate the development of tolerance to chronic administration of morphine in the rat. In the present study, we have investigated the expression of L- and N-type VSCC using immunohisto-chemistry, in the cervical region of the spinal cords from animals treated chronically with morphine alone or in combination with nimodipine. The highest expression of both VSCCs within the spinal cord was detected within the superficial laminae of the dorsal horn, which indicates that these channels play an important role in the spinal processing of pain.

Nimodipine is more effective than nifedipine in attenuating morphine tolerance on chronic co-administration in the rat tail-flick test.

Opioids, when co-administered with L-type calcium channel blockers (L-CCBs) show morphine like higher antinociceptive effect. This antinociceptive effect has been further investigated using a different experimental paradigm. The effect of two different L-CCBs (nifedipine and nimodipine) on morphine-induced antinociception was studied by the tail-flick test (40 min after morphine administration) in adult Wistar rats.

Intrathecal co-administration of morphine and nimodipine produces higher antinociceptive effect by synergistic interaction as evident by injecting different doses of each drug in rats.

Earlier, we reported that morphine-nimodipine combination produces significantly higher antinociception after intrathecal but not after systemic administration in mice. Different doses of morphine and nimodipine (5 microg of morphine, 5 microg of nimodipine, 5 microg each of morphine and nimodipine, 10 microg of morphine, 10 microg of nimodipine, 10 microg morphine with 5 microg nimodipine and 5 microg of morphine with 10 microg of nimodipine) were now injected intrathecally in Wistar rats to further characterise this antinociceptive effect. The acute antinociceptive effect was measured by the tail-flick test between 15 min to 7 h.

Enhanced analgesic effect of morphine-nimodipine combination after intraspinal administration as compared to systemic administration in mice.

Calcium plays an important role in the pathophysiology of pain. A number of studies have investigated the effect of L-type calcium channel blockers on the analgesic response of morphine. However, the results are conflicting.

Acute analgesic effect of loperamide as compared to morphine after intrathecal administration in rat.

Loperamide, a mu opioid receptor agonist, which is commonly used as an antidiarrhoeal agent has been reported to possess analgesic activity after intrathecal administration. However, the exact analgesic profile, i.e.