targeted-toxins

Harris RBS (2023) Low dose peripheral leptin infusion produces selective activation of ventromedial hypothalamic and hindbrain STAT3. Am J Physiol Endocrinol Metab doi: 10.1152/ajpendo.00083.2023 PMID: 37285599

Objective: To show that the deletion of leptin-receptor expressing cells in the ventromedial hypothalamus (VMH) has no effect on basal body weight or body fat mass, but greatly attenuates the inhibition of food intake.

Summary: This study evaluates leptin’s impact on hypothalamic pSTAT3 in leptin-infused versus injected rats. High-dose leptin suppressed food intake and reduced weight and fat mass without affecting energy metrics, with pSTAT3 increases observed in the VMH only during intake suppression and in the nucleus of the solitary tract over both short and extended periods. These results highlight the role of VMH and hindbrain receptors in mediating leptin’s effects on food intake and metabolic changes.

Usage: Leptin-SAP is referenced in Seamon et al 2019: Male Sprague-Dawley rats received bilateral VMH 75 nl injections of 260 ng/microliter of Leptin-SAP (IT-47) or Blank-Saporin (IT-21).

Related Products: Leptin-SAP (Cat. #IT-47), Blank-SAP (Cat. #IT-21)

See Also:

• Seamon M et al. Leptin receptor-expressing neurons in ventromedial nucleus of the hypothalamus contribute to weight loss caused by fourth ventricle leptin infusions. Am J Physiol Endocrinol Metab 317(4):E586-E596, 2019.

Keilholz A, Homan C, Schroeder A, Osman K, Smith C, Pathak I, Streeter K, Ozden I, Ma L, Lever T, Nichols N (2023) Tongue exercise-induced functional and structural upper airway plasticity in a rodent model of hypoglossal (XII) motor neuron loss. American Physiology Summit 2023 Meeting Abstracts 38(S1)

Objective: Examine if upper airway function/coordination can be improved in lower motor neuron (LMN) degeneration by tongue exercise-induced axis plasticity.

Summary: Tongue muscle weakness in patients with motor neuron diseases suggests a potential role for therapeutic exercise but lacks evidence due to lack of an appropriate model. Data suggests that tongue exercise in CTB-SAP rats results in enhanced XII motor plasticity and mitigates structural airway changes. In conclusion, tongue exercise appears to cause XII-tongue axis plasticity to improve upper airway function and coordination in the face of XII LMN degeneration.

Usage: The authors developed a novel rodent model using intralingual injections of CTB-SAP to induce targeted loss of XII motor neurons and motor output.

Related Products: CTB-SAP (Cat. #IT-14)

Chen CH, Tsai TC, Wu YJ, Hsu KS (2023) Gastric vagal afferent signaling to the basolateral amygdala mediates anxiety-like behaviors in experimental colitis mice. JCI Insight e161874. doi: 10.1172/jci.insight.161874 PMID: 37200091

Objective: This study aimed to characterize gut-to-brain signaling and brain circuitry responsible for anxiety-like behaviors in a mouse model of inflammatory bowel disease.

Summary: The researchers found that mice with experimental colitis induced by dextran sulfate sodium administration displayed increased anxiety-like behaviors, which were prevented by cutting the vagus nerve connecting the gut to the brain. Further experiments showed that silencing brain cells in the locus coeruleus that project to the basolateral amygdala reduced anxiety behaviors in the colitis mice.

Usage: CCK-SAP (250 ng/µl) or Blank-SAP (250 ng/µl) were unilaterally or bilaterally injected to rostral (0.5 µl) and caudal (0.5 µl) parts of the nodose ganglia using a beveled injection pipette controlled by a microprocessor-controlled injector at the speed of 50 nl/sec.

Related Products: CCK-SAP (Cat. #IT-31), Blank-SAP (Cat. #IT-21)

Sainz AE (2023) The effects of loss of orexin neurons on attention. William & Mary Thesis.

Objective: This paper examines the effects of loss of orexin neurons on attention in mice.

Summary: This undergraduate honors thesis from William & Mary tested attention in mice after selective loss of orexin neurons, which are important for arousal. The researchers found impairments in sustained attention and cognitive flexibility in the mice missing orexin neurons.

Usage: 0.5 µl of Orexin-B-SAP (0.4 µg/µl) or saline was administered to both sides of the lateral hypothalamus for 30 seconds using a 1 µl syringe.

Related Products: Orexin-B-SAP (Cat. #IT-20)

Choi P (2023) The VLM a1/c1 ca/npy neuronal projections to the perifornical area of the lateral hypothalamus and its functional role in glucoprivic feeding. Washington State Univ Thesis.

Objective: This dissertation aimed to determine the role of neuropeptide Y (NPY) receptor signaling from the ventrolateral medulla (VLM) catecholamine (CA) neurons in the lateral hypothalamus (LHA) for glucoprivic feeding.

Summary: The results showed that NPY receptor-expressing neurons in the perifornical area of the LHA are required for glucoprivic feeding evoked by 2-deoxyglucose. Furthermore, antagonism of NPY Y1 or Y2 receptors in the LHA attenuated feeding evoked by chemogenetic activation of VLM CA neurons, indicating NPY release from VLM neurons activates LHA NPY receptors to elicit glucoprivic feeding.

Usage: NPY-SAP (50 ng per 100 nL/site) or control Blank-SAP (50 ng per 100 nL/site) dissolved in 0.01 M phosphate buffer was infused slowly over a 5 minute period directly into the perifornical lateral hypothalamic (stereotaxic coordinate: 2.8 mm caudal from bregma, +/- 1.2 mm lateral to the midline, and -7.4 mm from the dura mater) through a pulled glass capillary pipette (30 µm tip diameter) connected to a Picospritzer. The rats were allowed at least 7 days for a full recovery from surgery and NPY-SAP-induced neuronal ablation.

Related Products: NPY-SAP (Cat. #IT-28), Blank-SAP (Cat. #IT-21)

Zhou Y, Zhang K, Wang F, Chen J, Chen S, Wu M, Lai M, Zhang Y, Zhou W (2023) Polypyrimidine tract binding protein knockdown reverses depression-like behaviors and cognition impairment in mice with lesioned cholinergic neurons. Front Aging Neurosci 15:1174341. doi: 10.3389/fnagi.2023.1174341 PMID: 37181622

Objective: Examine the mechanisms of how knockdown of the RNA-binding protein polypyrimidine tract binding protein (PTB) reverses depression-like behavior and cognition impairment in mice with lesioned cholinergic neurons.

Summary: A specific loss of cholinergic neurons in the horizontal limb of the diagonal band of broca (HDB) is correlated with depression and dysfunction of cognition in mice. The authors induced cholinergic neuron loss via injection of 192-IgG-SAP. This was followed by injection of either antisense oligonucleotides or adeno-associated virus-shRNA in the injured area of HDB to knockdown PTB. Knockdown of PTB by these two approaches was found to relieve depression-like behaviors and alleviate cognitive impairment and the findings suggest that supplementing cholinergic neurons after PTB knockdown may be a therapeutic approach to reverse depression-like behaviors and cognitive impairment.

Usage: 192 IgG-saporin (Cat. IT-01) was injected bilaterally into the HDB at a volume of 0.25 μl with a concentration of 1 μg/μL, per side.

Related Products: 192-IgG-SAP (Cat. #IT-01)

Yaksh TL, dos Santo G, Lemes J, Malange K (2023) Neuraxial drug delivery in pain management: An overview of past, present, and future. Anaesthesiology doi: 10.1016/j.bpa.2023.04.003

Objective: Activation of neuraxial nociceptive linkages leads to a high level of encoding of the message that is transmitted to the brain and that can initiate a pain state with its attendant emotive covariates. The authors review the encoding of this message and describe the how it is subject to regulation by pharmacological targeting of dorsal root ganglion and dorsal horn systems.

Summary: Authors provide an overview of the past, present and future directions of the biology, pharmacology and technology relevant to the use of the neuraxial route. SP-SAP was used as a neuraxial toxin to eliminate NK1R expressing cells, which characteristic of neurons known to be the second order neurons responding to C fiber input. Delivery of SP-SAP results in long-lasting loss of NK1 bearing dorsal horn neurons and analgesia.

Related Products: SP-SAP (Cat. #IT-07)

Wu D, Yu N, Gao Y, Xiong R, Liu L, Lei H, Jin S, Liu J, Liu Y, Xie J, Liu E, Zhou Q, Liu Y, Li S, Wei L, Lv J, Yu H, Zeng W, Zhou Q, Xu F, Luo MH, Zhang Y, Yang Y, Wang JZ (2023) Targeting a vulnerable septum-hippocampus cholinergic circuit in a critical time window ameliorates tau-impaired memory consolidation. Mol Neurodegener 18(1):23. doi: 10.1186/s13024-023-00614-7 PMID: 37060096

Objective: There is an urgent need to study the targeting strategy for the MS-hippocampus cholinergic pathway to rescue tau-impaired memory.

Summary: Abnormal tau accumulation and cholinergic degeneration are hallmark pathologies in the brains of patients with Alzheimer’s disease (AD). However, the sensitivity of cholinergic neurons to AD-like tau accumulation and strategies to ameliorate tau-disrupted spatial memory in terms of neural circuits still remain elusive. The authors found that cholinergic neurons with an asymmetric discharge characteristic in the MS-hippocampal CA1 pathway are vulnerable to tau accumulation. Photoactivating MS-CA1 cholinergic inputs within a critical 3 h time window during memory consolidation efficiently improved tau-induced spatial memory deficits in a theta rhythm dependent manner. 192-IgG-Saporin was used to create an Alzheimer’s Disease animal model.

Related Products: 192-IgG-SAP (Cat. #IT-01)

See Also:

• Dornan WA et al. Comparison of site-specific injections into the basal forebrain on water maze and radial arm maze performance in the male rat after immunolesioning with 192 IgG saporin. Behav Brain Res 82:93-101, 1996.

Karthikeyan R, Davies WIL, Gunhaga L (2023) Non-image-forming functional roles of OPN3, OPN4 and OPN5 photopigments. J Photochem Photobiol 15:100177. doi: 10.1016/j.jpap.2023.100177

Objective: To review recent studies that focus on the non-image-forming functional roles of the OPN3, OPN4, and OPN5 photopigments.

Summary: This publication explores the non-image-forming functions of OPN3, OPN4, and OPN5 photopigments, highlighting their roles in various physiological processes such as regulation of circadian rhythms, pupillary light responses, modulation of sleep, mood, and hormone secretion, providing insights into the diverse functions of these photopigments beyond vision.

Related Products: Melanopsin-SAP (Cat. #IT-44)

Nestor CC, Merkley CM, Lehman MN, Hileman SM, Goodman RL (2023) KNDy neurons as the GnRH pulse generator: Recent studies in ruminants. Peptides 164:171005. doi: 10.1016/j.peptides.2023.171005 PMID: 36990389

Objective: This publication aims to summarize and provide an overview of recent studies investigating the role of KNDy neurons as the pulse generator for gonadotropin-releasing hormone (GnRH) release in ruminants.

Summary: Recent studies in ruminants, specifically sheep and cows, have investigated the role of KNDy neurons in driving the pulsatile release of GnRH. These studies have demonstrated the rhythmic electrical activity of KNDy neurons, coinciding with the pulsatile secretion of GnRH in ewes, suggesting their central role as the pulse generator. Additionally, the expression patterns of genes related to KNDy neurons and GnRH pulsatility have been examined in cows, revealing variations throughout the estrous cycle and indicating a potential involvement of KNDy neurons in regulating GnRH release in this species. These findings contribute to our understanding of reproductive physiology in ruminants and have implications for both animal and human reproductive health.

Related Products: NKB-SAP (Cat. #IT-63)