Distribution and chemical coding of neurons in intramural ganglia of the porcine urinary bladder trigone

This study presents the distribution and chemical coding of neurons in the porcine intramural ganglia of the urinary bladder trigone (IG-UBT) demonstrated using combined retrograde tracing and double-labelling immunohistochemistry. Retrograde fluorescent tracer Fast Blue (FB) was injected into the wall of both the left and right side of the bladder trigone during laparotomy performed under pentobarbital anaesthesia. Ten-microm-thick cryostat sections were processed for double-labelling immunofluorescence with antibodies against tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), neuropeptide Y (NPY), somatostatin (SOM), galanin (GAL), vasoactive intestinal polypeptide (VIP), nitric oxide synthase (NOS), calcitonin gene-related peptide (CGRP), substance P (SP), Leu5-enkephalin (LENK) and choline acetyltransferase (ChAT). IG-UBT neurons formed characteristic clusters (from a few to tens neuronal cells) found under visceral peritoneum or in the outer muscular layer. Immunohistochemistry revealed four main populations of IG-UBT neurons: SOM- (ca. 35%), SP- (ca. 32%), ChAT- and NPY- immunoreactive (-IR) (ca. 23%) as well as non-adrenergic non-cholinergic nerve cells (ca. 6%). This study has demonstrated a relatively large population of differently coded IG-UBT neurons, which constitute an important element of the complex neuro-endocrine system involved in the regulation of the porcine urogenital organ function.     

Intramural neurons in the urinary bladder of the guinea-pig

Summary The urinary bladder of adult female guinea-pigs was stained histochemically to detect the presence of intramural ganglion neurons. Counts on wholemount preparations of entire bladders revealed the presence of 2000–2500 neurons per bladder, either as individual nerve cells or, more often, as ganglia containing up to 40 neurons. Both ganglia and single neurons lie along nerve trunks and are interconnected to form a plexus. Ganglia occur in every part of the bladder; they are more numerous on the dorsal than on the ventral wall, and they are especially abundant in an area within a radius of 800 m from the point of entry into the bladder wall of ureters and urinary arteries. The ganglia are located inside the muscle coat and close to muscle bundles; they usually lie nearer the mucosa than the serosa. Ultrastructurally, each ganglion is surrounded by a capsule; in addition to neurons and glial cells, the ganglia contain capillaries, collagen fibrils and fibroblasts; ganglion neurons are individually wrapped by glial cells and are separated from one another by connective tissue.     

Graphic representation of the distribution of acetylcholinesterase in cat dorsal root ganglion neurons

Synopsis Acetylcholinesterase (AChE) activity of primary sensory neurons of the cat has been quantitated and correlated with cell size. Dorsal root ganglia of the fourth and fifth thoracic spinal levels were studied. Frozen longitudinal and cross-sections were collected serially and stained with Cresyl Violet for total cell counts of the ganglia on the left; the average count was 3375 cells. Ganglia from the right were stained for AChE after the method of Karnovsky & Roots (1964) as modified by El Badawi & Schenk (1967), and counterstained with Haematoxylin. Cells were counted in every fourth section and the diameter of each was recorded. AChE-positive cells were classified as brown (B₁, B₂, B₃) and AChE-negative ones as blue (BL).An inverse correlation exists between cell size and AChE activity. High activity was demonstrated in 29% of the cells (B₁), moderate activity in 52% (B₂), minimal activity in 15% (B₃) and 4% were classified as AChE-negative (BL). Small cells with high activity were centrally located in the ganglia whereas large AChE-negative cells were peripherally distributed. Chi-Square analysis revealed that the size of the cell was not independent of the enzyme colour category.     

A comparative study of the urinary bladder and the intramural portion of the ureter.

The bladder belonging to eleven mammalian species were investigated, and as a result the following observations were made: (1) a submucous ureter was found in the case of most of the species examined; (2) histological investigation revealed three types of intramural ureters, and (3) downward extension of ureteric musculature, separate from bladder musculature, to the seminal colliculus in the male, or to the lower end of the urethra in the female, was found. A suggestion is presented to explain the manner by which the ureteric openings change their relations to those of the mesonephric ducts development. It seems that 'after absorption of the common segment of the Wolffian duct, breaking down of the ventral wall of ureter' is the most likely process.     

Molecular forms of acetylcholinesterase in frog skeletal muscle: effects of denervation

In the muscles of the frog, four main molecular forms of acetylcholinesterase are present, with sedimentation coefficients of 5.7, 10.4, 13 and 17.6 S. The heaviest forms, 13 S and 17.6 S are found in both nerve-free segments and endplates zones of sartorius muscle. They decrease in long-term denervation experiments. Consequently, these two forms are not specifically localized in endplates containing regions. However, they depend either on muscle activity or on neural influence or both.     

Interneuronal synapses in the local ganglia of the cat urinary bladder.

The interneuronal synapses of the urinary bladder in the cat were studied by electron microscopy. The great majority of the fibres containing vesicles are found within the ganglia occurring in the trigonum area. Morphologically differentiated synaptic contacts could be observed on the surface of the local neurons and between the different nerve processes. The presynaptic terminals can be divided into three types based on a combination of synaptic vesicles. Type I terminals, presumably cholinergic synaptic terminals, contain only small clear vesicles of 40-50 nm in diameter. Type II terminals, presumably adrenergic terminals, are characterized by small granulated vesicles of 40-60 nm in diameter. Type III terminals, probably of local origin, contain a variable number of large granulated vesicles of 80-140 nm in diameter. Occasionally, a single nerve fibre contacted several (two or four) other nerve processes forming a typical synapse. In other cases, on one nerve cell soma or on other nerve processes there are two or three different-type nerve terminals establishing synapses. It might be inferred from these observations that convergence and divergence can occur in the local ganglia and that cholinergic and adrenergic synaptic terminals can modulate the ganglionic activity. However, a local circuit also can play an important role in coordinating the function of the bladder.     

Electrophysiological effects of GABA on cat pancreatic neurons

In mammalian peripheral sympathetic ganglia GABA acts presynaptically to facilitate cholinergic transmission and postsynaptically to depolarize membrane potential. The GABA effect on parasympathetic pancreatic ganglia is unknown. We aimed to determine the effect of locally applied GABA on cat pancreatic ganglion neurons. Ganglia with attached nerve trunks were isolated from cat pancreata. Conventional intracellular recording techniques were used to record electrical responses from ganglion neurons. GABA pressure microejection depolarized membrane potential with an amplitude of 17.4 +/- 0.7 mV. Electrically evoked fast excitatory postsynaptic potentials were significantly inhibited (5.4 +/- 0.3 to 2.9 +/- 0.2 mV) after GABA application. GABA-evoked depolarizations were mimicked by the GABA(A) receptor agonist muscimol and abolished by the GABA(A) receptor antagonist bicuculline and the Cl(-) channel blocker picrotoxin. GABA was taken up and stored in ganglia during preincubation with 1 mM GABA; beta-aminobutyric acid application after GABA loading significantly (P < 0.05) increased depolarizing response to GABA (15.6 +/- 1.0 vs. 7.8 +/- 0.8 mV without GABA preincubation). Immunolabeling with antibodies to GABA, glial cell fibrillary acidic protein, protein gene product 9.5, and glutamic acid decarboxylase (GAD) immunoreactivity showed that GABA was present in glial cells, but not in neurons, and that glial cells did not contain GAD, whereas islet cells did. The data suggest that endogenous GABA released from ganglionic glial cells acts on pancreatic ganglion neurons through GABA(A) receptors.     

Ultrastructure of neurons of the myenteric plexus in the normal cat and after temporary circulatory interruption

Ultrastructural organization of neurons in the myenteric plexus of the cat small intestine has been studied in norm and after the blood stream had been switched off for 4 hours and 1, 3, 7, 30 days after recirculation. Ultrastructural uniformity of perikaryons is noted, therefore it is impossible to reveal electron microscopically neurons with different functional qualities. Four morphological types of preterminal dilatations of axons are revealed. Some neurons demonstrate certain resistance to the four hours' ischemia of the intestine, predominance of reactive processes in most of the cells. Dynamics of destructive and reparative processes are followed in neurons and their processes after recirculation.     

Differential effects of denervation on acetylcholinesterase activity in parasympathetic and sympathetic ganglia of the frog, Rana pipiens

The transsynaptic regulation of acetylcholinesterase (AChE) was studied by recording the changes in enzymatic activity following denervation in two types of autonomic ganglia in the frog, Rana pipiens. Opposite effects on AChE were found in the parasympathetic cardiac ganglion and in the sympathetic lumbar ganglion; denervation produced a significant increase in AChE activity in cardiac ganglia but a significant decrease in lumbar ganglia. The relative effects of denervation on intracellular and total AChE were examined by selectively inhibiting extracellular AChE with echothiophate, a poorly lipid-soluble cholinesterase inhibitor. Denervation resulted in a significant increase in intracellular AChE in cholinergic cardiac ganglia but had no effect on intracellular AChE activity in adrenergic lumbar ganglia. Histochemical studies revealed little change in extracellular AChE staining upon denervation in the cardiac ganglion, whereas in the lumbar ganglia there was a loss of AChE-specific reaction product. These results raise the possibility that the transsynaptic control of AChE activity by innervation in the frog is influenced by the transmitter synthetic properties of the postsynaptic ganglion cells.     

The effect of catecholamines on H+ and NH+4 excretion in toad urinary bladder

The catecholamines epinephrine and norepinephrine, when placed on the toad urinary bladder in vitro, at a final concentration of 50 microM, caused a significant increase in H+ and NH+4 excretion by the bladder. Isoprenaline in a final concentration of 50 microM also increased H+ and NH+4 excretion in the bladder. Propranolol at a concentration of 50 microM blocked the stimulation of H+ excretion by isoprenaline but propranolol at 100 microM was required to block the stimulation of NH+4 by isoprenaline. The dose-response analysis indicates that the concentration of epinephrine used (50 microM) is at or near the maximal effective dose. These findings indicate that catecholamines stimulate H+ and NH+4 excretion in the toad urinary bladder and evidence suggests this may be mediated via the beta receptor mechanism.