Botulinum toxin type A-induced changes in the chemical coding of dorsal root ganglion neurons supplying the porcine urinary bladder: Botulinum toxin type A (BTX) is a potent neurotoxin, which in recent years has been effectively applied in experimental treatments of many neurogenic disorders of the urinary bladder. BTX is a selective, presynaptically-acting blocking agent of acetylcholine release from nerve terminals what, in turn, leads to the cessation of somatic motor and/or parasympathetic transmission. However, application of this toxin in urological practice is still in the developmental stages and the full mechanism of its action remain elusive. Thus, the present study was aimed at investigating the neurochemical characterization of dorsal root ganglion (DRG) neurons supplying the porcine urinary bladder after BTX treatment. Retrograde tracer Fast Blue (FB) was injected into the urinary bladder wall in six juvenile female pigs and three weeks later, intramural bladder injections of BTX (100 IU per animal) were carried out in all the animals. After a week, DRG from L1 to Cq1 were harvested from the pigs and neurochemical characterization of FB⁺ neurons was performed using double-labeling immunofluorescence technique on 10-μm-thick cryostat sections. BTX injections led to a significant decrease in the number of FB⁺ neurons containing substance P (SP), calcitonin gene-related peptide (CGRP), calbindin (CB), somatostatin (SOM) and neuronal nitric oxide synthase (nNOS) when compared with that found in the healthy animals (19% vs. 45%, 18% vs. 36%, 0.6% vs. 3%, 0.4 vs. 4% and 0.1% vs. 6%, respectively) These data demonstrated that BTX changed the chemical coding of bladder sensory neurons, and therefore this drug should be taken into consideration when it planning experimental therapy of selected neurogenic bladder disorders.

Botulinum toxin (BTX) is a potent neurotoxin which blocks acetylcholine release from nerve terminals, and therefore leads to cessation of somatic motor and/or parasympathetic transmission. Recently it has been found that BTX also interferes with sensory transmission, thus, the present study was aimed at investigating the neurochemical characterization of substance P-immunoreactive (SP-IR) bladder-projecting sensory neurons (BPSN) after the toxin treatment. Investigated neurons were visualized with retrograde tracing method and their chemical profile was disclosed with double-labelling immunohistochemistry using antibodies against SP, calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase activating polypeptide (PACAP), neuronal nitric oxide synthase (nNOS), galanin (GAL), calbindin (CB), and somatostatin (SOM). In the control group (n = 6), 45% of the total population of BPSN were SP-IR. Nearly half of these neurons co-expressed PACAP or CGRP (45% and 35%, respectively), while co-localization of SP with GAL, nNOS, SOM or CB was found less frequently (3.7%, 1.8%, 1.2%, and 0.7%, respectively). In BTX-treated pigs (n = 6), toxin-injections caused a decrease in the number of SP-IR cells containing CGRP, SOM or CB (16.2%, 0.5%, and 0%, respectively) and a distinct increase in these nerve cells immunopositive to GAL (27.2%). The present study demonstrates that BTX significantly modifies the chemical phenotypes of SP-IR BPSN.

Neurodegenerative diseases are a group of disorders characterized by the progressive deterioration of the structure and function of central nervous system neurons and include, among others, amyotrophic lateral sclerosis (ALS), multiple sclerosis (MS), Parkinson’s (PD), Alzheimer’s (AD), and Huntington’s (HD) diseases. And while all these diseases seem to have different genetic and environmental components, growing evidence shows that they share common underlying pathological features such as increased neuroinflammation and excessive oxidative stress. RAGE, the receptor for advanced glycation end-products, is a signal transduction receptor, and its activation triggers an increase in proinflammatory molecules, oxidative stressors, and cytokines. Diaph1, protein diaphanous homolog 1, is an actin modulator and an intracellular ligand of RAGE. Studies demonstrated that RAGE and Diaph1 act together, and their downstream signaling pathways play a role in neurodegeneration. Here, based on current evidence and our own research, we provide an overview of the RAGE–Diaph1 signaling and discuss the therapeutic potential of targeted therapy aimed at RAGE–Diaph1 signaling inhibition in the prevention and treatment of neurodegenerative diseases.

The present study investigated the influence of intravesically instilled resiniferatoxin (RTX) or tetrodotoxin (TTX) on the distribution, number, and chemical coding of noradrenergic and cholinergic nerve fibers (NF) supplying the urinary bladder in female pigs. Samples from the bladder wall were processed for double-labelling immunofluorescence with antibodies against cholinergic and noradrenergic markers and some other neurotransmitter substances. Both RTX and TTX caused a significant decrease in the number of cholinergic NF in the urinary bladder wall (in the muscle coat, submucosa, and beneath the urothelium). RTX instillation resulted in a decrease in the number of noradrenergic NF in the submucosa and urothelium, while TTX treatment caused a significant increase in the number of these axons in all the layers. The most remarkable changes in the chemical coding of the NF comprised a distinct decrease in the number of the cholinergic NF immunoreactive to CGRP (calcitonin gene-related peptide), nNOS (neuronal nitric oxide synthase), SOM (somatostatin) or VIP (vasoactive intestinal polypeptide), and an increase in the number of noradrenergic NF immunopositive to GAL (galanin) or nNOS, both after RTX or TTX instillation. The present study is the first to suggest that both RTX and TTX can modify the number of noradrenergic and cholinergic NF supplying the porcine urinary bladder.

Although guanethidine (GUA) was used in the past as a drug to suppress hyperactivity of the sympathetic nerve fibers, there are no available data concerning the possible action of this substance on the sensory component of the peripheral nervous system supplying the urinary bladder. Thus, the present study was aimed at disclosing the influence of intravesically instilled GUA on the distribution, relative frequency, and chemical coding of dorsal root ganglion neurons associated with the porcine urinary bladder. The investigated sensory neurons were visualized with a retrograde tracing method using Fast Blue (FB), while their chemical profile was disclosed with single-labeling immunohistochemistry using antibodies against substance P (SP), calcitonin gene-related peptide (CGRP), pituitary adenylate cyclase activating polypeptide (PACAP), galanin (GAL), neuronal nitric oxide synthase (nNOS), somatostatin (SOM), and calbindin (CB). After GUA treatment, a slight decrease in the number of FB⁺ neurons containing SP was observed when compared with untreated animals (34.6 ± 6.5% vs. 45.6 ± 1.3%), while the number of retrogradely traced cells immunolabeled for GAL, nNOS, and CB distinctly increased (12.3 ± 1.0% vs. 7.4 ± 0.6%, 11.9 ± 0.6% vs. 5.4 ± 0.5% and 8.6 ± 0.5% vs. 2.7 ± 0.4%, respectively). However, administration of GUA did not change the number of FB⁺ neurons containing CGRP, PACAP, or SOM. The present study provides evidence that GUA significantly modifies the sensory innervation of the porcine urinary bladder wall and thus may be considered a potential tool for studying the plasticity of this subdivision of the bladder innervation.