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The frog is a useful model to study the structure and function of intracardiac neurons. The goal of this study was to evaluate the size and distribution of synaptic boutons on the intracardiac neurons in the frog Rana temporaria. Interatrial septa from four animals were double-labelled immunohistochemically for the cholinergic marker choline acetyltransferase (ChAT) and the marker of synaptic vesicles synaptophysin (SYP). One hundred intracardiac neurons were analysed by confocal microscopy. Terminals of preganglionic axons were strongly positive for ChAT, while synaptic boutons were strongly positive for both ChAT and SYP. The number of synaptic boutons per neuron ranged from 2 to 121 and was 10±2 (mean±SE). The total area of synaptic boutons ranged from 6 μm 2 to 270 μm 2 and was 98±6 μm 2 . The largest total area of synaptic boutons was found on the axonal half of neuronal soma (59±4 μm 2 ). The total areas of synaptic boutons on both the non-axonal half of soma and the proximal axon were smaller (36±3 μm 2 ; 6±2 μm 2 ; P<0.001). Synaptic boutons occupied 13±1% of the area of the neuronal soma profile. Conclusions: 1) The axonal half of the soma of the frog intracardiac neuron is more densely innervated than the non-axonal half of the soma. 2) The axosomatic and axoaxonic synapses are present on frog intracardiac neurons. The study provides a framework for further experimental studies on the formation and rearrangement of synapses on frog intracardiac neurons.

Background. Most multiple sclerosis (MS) cases are sporadic, however about 20 percent are hereditary [2]. It is still unclear whether heredity affects the progression and severity of the disease. The aim of this study is to assess the effect of heredity on the development of multiple sclerosis and on the course of disease by analyzing the results of disability, severity scales and clinical studies, and comparing them with sporadic cases. Methods. Our study included 104 patients with MS. The study group was comprised of 38 patients with family history of MS; the control group consisted of 66 patients with no family history. The survey included questions about demographic and clinical characteristics. Diagnostic results were evaluated retrospectively from medical records. Disability assessment was made according to EDSS. MSSS score was calculated using conversion table. Results. Patients with a family history tend to have slower onset of the disease, while control group is more likely to have an acute onset (p <0.001). Study group more often complained of symptoms related to pyramidal (74 % vs. 50 %) and brainstem (68 % vs. 20 %), cognitive dysfunction (47 % vs. 20 %), headache (37 % vs. 9 %), back pain (32 % vs. 9 %) than those in control group, p <0.05. EDSS and MSSS scores were higher in familiar cases (p <0.05). The number of exacerbations per year was also higher in study group (1.4 vs. 0.8; p <0.05). Patients with a family history have a higher incidence of MRI changes in brainstem (74% vs. 30%) and cerebellum (58% vs. 30%) than the control group (p <0.01). Conclusions. Patients with a family history tend to have slower onset of the disease, while control group is more likely to have an acute onset. Patients with a family history of MS more often complained of brainstem and cortical dysfunction, and pain in head or back. Both EDSS and MSSS scores were higher in familiar cases. They also have a higher number of exacerbations per year. Patients with a family history have a higher incidence of MRI changes in brainstem and cerebellum.