Chemical coding of inferior mesenteric ganglion (IMG) neurons supplying porcine ureters
Article published in Urologia Polska 2008/61/Supl. 1.

authors

Izabela Janiuk, Agnieszka Bossowska, Joanna Wojtkiewicz, Cezary Skobowiat, Hanna Mańkowska-Pliszka, Piotr Radziszewski, Mariusz Majewski

Katedra Morfologii Kręgowców Akademii Podlaskiej w Siedlcach
Katedra Fizjologii Człowieka Wydziału Nauk Medycznych Uniwersytetu Warmińsko-Mazurskiego w Olsztynie
Klinika Urologii Ogólnej, Onkologicznej i Czynnościowej Warszawskiego Uniwersytetu Medycznego

summary

Introduction.

As of now, data concerning the pattern of the chemical coding of inferior mesenteric ganglion (IMG) neurons involved in the innervation of the ureter in various mammals including pig, a very good model for the human organ, are still very incomplete. Thus, there is still paucity in data not only dealing with the co-incidence pattern of particular neurotransmitters in sympathetic neurons controlling the functions of the ureter, but also with these dealing with the sources of origin of sympathetic nerves supplying the organ.

Objectives.

We aimed the present study at unraveling the detailed distribution pattern of retrogradely labelled IMG neurons projecting to the porcine ureter and at disclosing their pattern of neurochemical coding

Materials and methods.

After multiple injections of the retrograde tracer Fast Blue (FB) into the wall of the right ureter in six juvenile female pigs, three weeks later animals were sacrificed and bilateral IMGs were collected for further studies. The chemical coding of retrogradely labelled IMG neurons was studied by means of routine double-immunofluorescence technique using primary antisera raised in different species. These included antibodies directed against dopamine-β-hydroxylase (DβH; as a marker of noradrenergic cells), neuropeptide Y (NPY), galanin (GAL), calbindin (CALB), vasoactive intestinal peptide (VIP), vesicular acetylcholine transporter (VAChT), pituitary adenylate cyclase-activating peptide (PACAP), serotonin (5-HT), Leu5-enkephalin (LENK), nitric oxide synthase (NOS), somatostatin (SOM), substance P (SP) and calcitonin gene-related peptide (CGRP).

Results.

Retrogradely labeled neurons supplying the ureter were observed in both, right and left IMGs, without any specific pattern of their intraganglionic distribution: FB+ cells were randomly dispersed throughout the ganglia, sporadically forming neuronal clusters composed of up to 5 cells. The vast majority of all FB+ neurons was DβH immunoreactive (DβH-IR; 96%), including both the medium-, as well as the small-sized cells. Of them, approximately 88% was simultaneously NPY-IR, and more than 85% contained additionally CALB. Neurons containing simultaneously FB, DβH and GAL were distinctly less numerous (up to 8%), while FB+/DβH+/LENK+ neurons were only sporadically encountered. FB+ neurons were immunonegative to all remaining substances studied, although they were supplied by numerous (PACAP-, VAChT-, LENK- or CGRP-IR), moderately numerous (VIP-, SOM- or SP-IR) or scarce (GAL-, 5-HT- or NOS-IR) varicose nerve fibers

Conclusions.

As may be judged from the present results, sympathetic innervation of the ureter originate in bilateral inferior mesenteric ganglia, and neurons projecting to the organ belong in their majority to DβH/NPY/CALB-IR population of IMG neurons, which are, most probably, involved in the neural control of vascular and non-vascular smooth muscles of the ureter. Physiological relevance of sympathetic GAL- or LENK-IR neurons supplying the ureter remains obscure yet.