Neural Control of the Gallbladder: An Intracellular Study of Human Gallbladder Neurons

Abstract

Background/Aims: Gallbladder neurons are important governors of gallbladder function. In animal models, gallbladder ganglia can be regulated both by neural and hormonal inputs. The purpose of this study was to demonstrate the feasibility of obtaining recordings from human gallbladder neurons. Methods: Human gallbladders (n = 33) were bathed in oxygenated Krebs solution (37°C) containing the vital fluorescent stain 4-Di-2-ASP to localize the ganglia. Cells were characterized using conventional intracellular recording techniques. Results: The mean resting membrane potential of human gallbladder neurons was –51.2 ± 1.8 mV (n = 11). Depolarizing current pulses elicited only 1–4 spikes regardless of the amplitude or duration of the stimulus. Afterspike hyperpolarizations had a mean duration of 144.5 ± 19.2 ms (n = 10). Anodal break excitation was not recorded with hyperpolarizing current pulses. Fiber tract stimulation elicited fast excitatory postsynaptic potentials in all neurons tested. Conclusion: Intracellular recordings of human gallbladder neurons utilizing 4-Di-2-ASP are thus feasible, but are very problematic due to the density of connective tissue overlying the ganglia. As human and guinea pig gallbladder neurons have similar basic electrical properties, the guinea pig may be an appropriate model for further electrophysiological studies into gallbladder disease.

Innervation of the extrahepatic biliary tract

“…Neurons in the gallbladder ganglia in the guinea pig and man have identical electrophysiological properties (Mawe, 1990, 2000; Hillsley et al, 1998). Their properties indicate that these are relatively inexcitable neurons that require synaptic input, from extrinsic sources such as the vagus nerves, to generate ganglionic output.…”

“…Depolarizing current pulses elicit only 1–4 spikes regardless of the amplitude or duration of the stimulus. After spike, hyperpolarizations have a mean duration of about 150 msec (Mawe, 1990; Hillsley et al, 1998). Gallbladder gliocytes have a resting membrane potential of about −70 mV, low input resistance, do not fire action potentials in response to intracellular injection of large current pulses, and do not receive synaptic input (Mawe, 1990).…”

Selective visualisation of neuroepithelial bodies in vibratome slices of living lung by 4-Di-2-ASP in various animal species

“…Styryl pyridinium dyes seem to be good candidates for the vital staining of NEBs in fresh lung slices, especially 4-(4-diethylaminostyryl)-N-methylpyridinium iodide (4-Di-2-ASP), which appears to label neuroendocrine cells specifically in the skin (Nurse and Farraway 1989). Originally, 4-Di-2-ASP was used to visualise motor nerve terminals (Kelly et al 1985;Magrassi et al 1987;Lichtman et al 1987;Herrera and Banner 1990), nerve fibres in autonomic ganglia (Hanani 1992) and neuronal cell bodies in the choroid (Bergua et al 1994;Schrödl et al 2003), the enteric nervous system (Cornelissen et al 1996) and the gallbladder (Hillsley et al 1998). Whereas its exact staining mechanism is still unclear, 4-Di-2-ASP is known to be taken up in the plasma membrane and later on in mitochondria of living excitable cells (Loew et al 1985).…”

Intrinsic Choroidal Neurons in the Human Eye: Projections, Targets, and Basic Electrophysiological Data

“…This dye has no influence on basic electrophysiological neuronal features. 15,16,18,19 Although agarose has been used earlier to prevent single neurons or tissue slices from moving in the recording chamber, 20 -23 we used it, to our knowledge, for the first time on vital wholemount preparations followed by immunohistochemistry. Comparison of the staining technique using the vital fluorescent dye 4-Di-2-ASP in agarose-treated versus nontreated tissue yielded no differences.…”