Mambalgins are peptide inhibitors of acid-sensing ion channels type 1 (ASIC1) with potent analgesic effects in models of inflammatory and neuropathic pain. To optimize recombinant peptide production and enhance pharmacological properties, we developed a mutant analog of mambalgin-1 (Mamb) through molecular modeling and site-directed mutagenesis. The resulting peptide, Mamb-AL, features methionine-to-alanine and methionine-to-leucine substitutions, allowing for a more efficient recombinant production protocol in E. coli. Electrophysiological experiments demonstrated that Mamb-AL exhibits three-fold and five-fold greater inhibition of homomeric ASIC1a and ASIC1b channels, respectively, and a two-fold increase in inhibition of heteromeric ASIC1a/3 channels compared with Mamb. In a mouse model of acetic acid-induced writhing pain, Mamb-AL showed a trend toward stronger analgesic efficacy than the wild-type peptide. These improvements in both production efficiency and pharmacological properties make Mamb-AL a valuable tool for studying ASIC channels and a promising candidate for analgesic drug development.

The TRPV1 channel is actively involved in various neuronal processes and is found in various structures of the nervous system, including peripheral and central neurons, sensory ganglia, spinal cord, and various parts of the brain. Due to its ability to respond to various stimuli, TRPV1 can have a significant impact on the body’s responses to stress. Studies indicate the involvement of TRPV1 in the regulation of anxiety behavior. Suppression of TRPV1 activity leads to a decrease in the level of anxiety in animals, which indicates the importance of this channel in psychoemotional regulation. A promising compound for inhibiting this channel is the APHC3 peptide, which is a selective receptor antagonist. The results obtained this study show that this peptide has a pronounced anxiolytic effect, reducing the level of anxiety in the studied animals.

One of the attractive targets for the relief of stress conditions is TRPV1, which is expressed mostly in primary afferent neurons (nociceptors) and in the central nervous system, mainly in the cortex and hippocampus. We evaluated the action of a potent low-molecular-weight antagonist of TRPV1 (AMG517) and peptide modulator of this channel (APHC3) on long-term potentiation (LTP) and Paired-Pulse Ratio (PPR) in the CA3-CA1 region of the hippocampus of mice. In vivo, we used intranasal administration to provide effective peptide delivery into the brain and analyzed the effects of APHC3 in acute stress tests in comparison with intramuscular administration of APHC3, AMG517, and the reference anxiolytic drug Fabomotizole (Fab). In electrophysiology studies, APHC3 significantly enhanced LTP and PPR, while AMG517 enhanced only PPR. Intranasal administration of APHC3 to mice provided a moderate anxiolytic effect in the single dose (0.01 mg/kg). Intramuscular administration of APHC3 and AMG517 significantly reduced acute stress in mice equal to the reference drug Fab. Thus, TRPV1 modulation in either the peripheral or central nervous system is sufficient to produce an anxiolytic-like effect, likely through distinct underlying mechanisms.

The translational model of experimental stroke in rats induced by a gas embolism was created to clarify the features of stroke's development and to evaluate the neuroprotective effect of novel remedies and proven drugs. The moderately time and labor-consuming protocol allows for observing the dynamics of rapid neuron death in awake animals, providing a unique opportunity to assess the acute phase of stroke, including delirium, as well as to monitor autonomic disturbances such as changes in blood pressure, body temperature, and respiratory minute volume. Atmospheric air (100 µL) was administered by infusion through a vascular catheter placed retrogradely into the common carotid artery via the external carotid artery, using an infusion pump. Twenty-four hours after embolization, the animals exhibit stereotypical behavioral, motor deficits, and histopathological differences. By the seventh day of the experiment, a significant improvement in neurological status was observed, and the results in behavioral tests approached those of the control values. At the same time, a transition from neutrophilic to macrophage infiltration is observed in the ischemic lesion. The proposed model can be utilized in preclinical studies, as it reproduces the neuropsychiatric complications of the post-stroke period, along with the corresponding physiological, functional, and histopathological changes.

TRPV1, which plays a key role in transmitting pain signals, is widely distributed in various tissues and cells, including the central nervous system. Activation or suppression of TRPV1 influences neuronal desensitization, pain signal transmission, and regulation of neurotransmitter systems. The APHC3 peptide, as a selective antagonist of TRPV1, is used to investigate the effects of blocking this channel in terms of anxiety and stress response in mice. The results of studies can indicate the influence of TRPV1 on the formation of emotional states. This study is important for understanding the impact of TRPV1 channels on stress in ICR mice, being promising for further research in the field of biomedicine and biomodeling.