The Influence of Tetrodotoxin (TTX) on the Distribution and Chemical Coding of Caudal Mesenteric Ganglion (CaMG) Neurons Supplying the Porcine Urinary Bladder

Abstract

The treatment of micturition disorders creates a serious problem for urologists. Recently, new therapeutic agents, such as neurotoxins, are being considered for the therapy of urological patients. The present study investigated the chemical coding of caudal mesenteric ganglion (CaMG) neurons supplying the porcine urinary bladder after intravesical instillation of tetrodotoxin (TTX). The CaMG neurons were visualized with retrograde tracer Fast blue (FB) and their chemical profile was disclosed with double-labeling immunohistochemistry using antibodies against tyrosine hydroxylase (TH), neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP), somatostatin (SOM), calbindin (CB), galanin (GAL) and neuronal nitric oxide synthase (nNOS). It was found that in both the control (n = 6) and TTX-treated pigs (n = 6), the vast majority (92.6% ± 3.4% and 88.8% ± 2%, respectively) of FB-positive (FB+) nerve cells were TH+. TTX instillation caused a decrease in the number of FB+/TH+ neurons immunopositive to NPY (88.9% ± 5.3% in the control animals vs. 10.6% ± 5.3% in TTX-treated pigs) or VIP (1.7% ± 0.6% vs. 0%), and an increase in the number of FB+/TH+ neurons immunoreactive to SOM (8.8% ± 1.6% vs. 39% ± 12.8%), CB (1.8% ± 0.7% vs. 12.6% ± 2.7%), GAL (1.7% ± 0.8% vs. 10.9% ± 2.6%) or nNOS (0% vs. 1.1% ± 0.3%). The present study is the first to suggest that TTX modifies the chemical coding of CaMG neurons supplying the porcine urinary bladder.

The Influence of Resiniferatoxin (RTX) and Tetrodotoxin (TTX) on the Distribution, Relative Frequency, and Chemical Coding of Noradrenergic and Cholinergic Nerve Fibers Supplying the Porcine Urinary Bladder Wall

“…However, the present results suggest that the therapeutic effect observed after the toxin treatment can be a result of not only the inhibitory influence on the C-fibers but also involves changes (presumably beneficial) in the distribution and chemical coding of the cholinergic and adrenergic axons. The present data are partially supported by our previous findings, as we already have revealed that intravesically instilled RTX influences immunohistochemical characteristics of sympathetic chain ganglia urinary bladder-projecting neurons [ 17 ] and that both RTX and TTX induce plastic changes in caudal mesenteric ganglia urinary bladder-projecting neurons [ 18 , 19 ].…”

The Influence of an Adrenergic Antagonist Guanethidine on the Distribution Pattern and Chemical Coding of Caudal Mesenteric Ganglion Perikarya and Their Axons Supplying the Porcine Bladder

“…A thorough discussion regarding the distribution, relative frequency, and chemical coding of both noradrenergic nerve fibers and CaMG neurons supplying the wall of the female porcine urinary bladder was already presented in our previous papers [ 42 , 43 ]. However, it should be stressed that in both previous studies control groups were slightly different: while in the case of the study focusing on intramural noradrenergic nerve fibers [ 42 ], no medical procedures were applied to the control pigs, in studies concerning the neurochemical characteristics of the noradrenergic CaMG neurons supplying the porcine urinary bladder, the control pigs were either intravesically instilled with 5% aqueous solution of ethyl alcohol [ 43 ], or with citrate buffer (present experiment).…”

“…A thorough discussion regarding the distribution, relative frequency, and chemical coding of both noradrenergic nerve fibers and CaMG neurons supplying the wall of the female porcine urinary bladder was already presented in our previous papers [ 42 , 43 ]. However, it should be stressed that in both previous studies control groups were slightly different: while in the case of the study focusing on intramural noradrenergic nerve fibers [ 42 ], no medical procedures were applied to the control pigs, in studies concerning the neurochemical characteristics of the noradrenergic CaMG neurons supplying the porcine urinary bladder, the control pigs were either intravesically instilled with 5% aqueous solution of ethyl alcohol [ 43 ], or with citrate buffer (present experiment). The aim of the abovementioned procedures performed in all the control pigs was to guarantee that changes in the distribution and chemical coding of bladder noradrenergic nerve fibers and CaMG neurons observed after the treatment with toxins (botulinum toxin type A and resiniferatoxin in the previous studies) as well as the GUA (this study) were caused by these biological active substances themselves, and not due to factors associated with the technique and route of their administration.…”

“…Double-immunofluorescence labelings were performed on cryostat sections prepared from each of the urinary bladder wall samples, as well as sections of right and left CaMG ganglia (selected from three different representative regions of the ganglion, located at upper one-third, middle and lower one-third, respectively), according to a previously described method [ 129 ]. The presence of all neurotransmitters (NPY, SOM, CB, VIP, GAL) or their markers (DβH, TH, nNOS; enzymes of the catecholamine or nitric oxide biosynthesis pathway, respectively), was previously revealed either in the intramural nerve fibers of the porcine urinary bladder [ 42 , 130 ] and/or in the CaMG-bladder projecting neurons of the pig [ 43 , 131 ]. It should be stressed that although both enzymes of the catecholamine synthesis pathway are synthesized in the cell body, DβH is very quickly transported from the cell body to the axon, which means that under physiological conditions, cell soma contains significantly fewer DβH molecules than TH, which makes it difficult to clearly determine under a light microscope, whether the studied ganglion cell belongs to the noradrenergic or non-adrenergic population.…”

A study on preganglionic connections and possible viscerofugal projections from urinary bladder intramural ganglia to the caudal mesenteric ganglion in the pig

“…Although the morphology and chemical coding of CaMG neurons have been described in detail both in humans and in many animal species (e.g. Furness, 2015;Sienkiewicz et al 2015;Lepiarczyk et al 2017), the literature in the field contains only fragmentary data on the localization and chemical characteristics of SPN projecting to this ganglion. Detailed knowledge concerning the arrangement of autonomic pathways to different organs is mostly limited to the postganglionic connections and is thus incomplete because it does not include the preganglionic component.…”