Synaptic transmission in submucosal ganglia of guinea pig distal colon

1991 ◽  
Vol 260 (6) ◽  
pp. G842-G849 ◽  
Author(s):  
T. Frieling ◽  
H. J. Cooke ◽  
J. D. Wood
Keyword(s):  
Guinea Pig ◽  
Ganglion Cells ◽  
Input Resistance ◽  
Distal Colon ◽  
Presynaptic Muscarinic Receptors ◽  
The Neural Networks ◽  
Type 3 ◽  
Prolonged Response

Intracellular electrical recording was used to investigate synaptic behavior of ganglion cells in the neural networks of the submucosal plexus of the guinea pig distal colon. Fast excitatory postsynaptic potentials (EPSPs), mediated by nicotinic receptors, were found in all S/type 1 neurons, 70% of AH/type 2, 75% of type 3, and 95% of type 4 neurons. Slow EPSPs were characterized by membrane depolarization, increased input resistance, enhanced action potential discharge, and suppression of hyperpolarizing afterpotentials in 64% of the S/type 1 neurons, 74% of AH/type 2, 31% of type 3, and 70% of type 4 neurons. Micropressure application of acetylcholine evoked a two-component depolarizing response consisting of an initial transient with decreased input resistance followed by a prolonged depolarization associated with increased input resistance. The transient response was suppressed by nicotinic-blocking drugs. Muscarinic antagonists suppressed the prolonged response. Acetylcholine acted also at presynaptic muscarinic receptors to suppress stimulus-evoked fast EPSPs. No stimulus-evoked inhibitory synaptic potentials were observed. Norepinephrine, applied by microejection, acted at alpha 2-adrenoceptors to hyperpolarize the membrane potential in association with decreased neuronal input resistance.

Electrophysiological properties of neurons in submucosal ganglia of guinea pig distal colon

1991 ◽  
Vol 260 (6) ◽  
pp. G835-G841 ◽  
Author(s):  
T. Frieling ◽  
H. J. Cooke ◽  
J. D. Wood
Keyword(s):  
Guinea Pig ◽  
Ganglion Cells ◽  
Distal Colon ◽  
Submucosal Plexus ◽  
Electrophysiological Properties ◽  
Small Intestinal ◽  
Type 3

Intracellular recording methods were used in vitro to study the electrophysiological behavior of neurons in ganglia of the submucosal plexus in the distal colon of the guinea pig. The results revealed subpopulations of submucosal ganglion cells that corresponded to the AH/type 2, S/type 1, type 3, and type 4 subpopulations found elsewhere in the intestine. Electrical behavior of colonic submucosal neurons differed from the myenteric plexus of the colon, rectum, and stomach and the small intestinal submucosal plexus mainly in the relative proportions of the different subpopulations. Regional differences in this respect may be a reflection of functional specialization in the diverse regions of the alimentary canal.

Elevation of cAMP facilitates noradrenergic transmission in submucous neurons of guinea pig ileum

1993 ◽  
Vol 264 (3) ◽  
pp. G442-G446 ◽  
Author(s):  
D. H. Zafirov ◽  
H. J. Cooke ◽  
J. D. Wood
Keyword(s):  
Guinea Pig ◽  
Ganglion Cells ◽  
Phosphodiesterase Inhibitor ◽  
Input Resistance ◽  
Guinea Pig Ileum ◽  
Synaptic Excitation ◽  
Before And After ◽  
Intracellular Microelectrodes

Slow synaptic excitation and inhibition were studied with intracellular microelectrodes in submucous ganglion cells of the guinea pig ileum. Elevation of adenosine 3',5'-cyclic monophosphate (cAMP) after application of forskolin or the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) resulted in slowly activating depolarization of the membrane potential. The depolarization was associated with increased input resistance, enhanced excitability, and suppression of hyperpolarizing afterpotentials. This occurred in AH/type 2 but not S/type 1 neurons. The action of forskolin or IBMX mimicked slow synaptic excitation in the same neurons. Focal electrical stimulation also evoked slow inhibitory postsynaptic potentials (IPSPs). The amplitude and duration of the IPSPs were increased by forskolin or a membrane-permeant analogue of cAMP. Treatment with phentolamine, yohimbine or idazoxan suppressed the IPSPs before and after potentiation by forskolin, suggesting that the IPSPs were mediated by release of norepinephrine acting at alpha 2-adrenoceptors. Application of adenosine or selective adenosinergic A1 agonists suppressed or abolished the IPSPs. The results suggest that elevation of cAMP facilitates the release of norepinephrine at alpha 2-synapses on submucous neurons of guinea pig small bowel.

Effects of PACAP on morphologically identified myenteric neurons in guinea pig small bowel

1993 ◽  
Vol 264 (3) ◽  
pp. G414-G421 ◽  
Author(s):  
F. L. Christofi ◽  
J. D. Wood
Keyword(s):  
Small Bowel ◽  
Adenylate Cyclase ◽  
Guinea Pig ◽  
Glial Cells ◽  
Input Resistance ◽  
Myenteric Neurons ◽  
Adenosine Receptor Agonist ◽  
Excitatory Responses

Intracellular microelectrodes were used to examine the actions of pituitary adenylate cyclase-activating peptide (PACAP) on morphologically identified myenteric neurons and glial cells of the guinea pig small bowel. PACAP-27 and PACAP-38 evoked excitatory responses in 96% of after hyperpolarizing (AH)/type 2 neurons. The half-maximal concentration for PACAP-27 was 1.5 nM. The responses consisted of membrane depolarization in association with increased input resistance, suppression of hyperpolarizing afterpotentials, and repetitive spike discharge. Forskolin mimicked the action of PACAP in all AH/type 2 neurons. PACAP excited 36% of S/type 1 neurons. Most of the AH/type 2 neurons had Dogiel II morphology, whereas the S/type 1 neurons were uniaxonal with morphology characteristics of Dogiel I or filamentous neurons. No glial cells responded to PACAP. A selective A1 adenosine receptor agonist blocked the excitatory action of PACAP, and this was reversed by a selective A1 antagonist. The results suggest that excitatory PACAP receptors and inhibitory adenosine A1 receptors are linked to adenylate cyclase in AH/type 2 myenteric neurons.

Histamine receptors on submucous neurons in guinea pig colon

1993 ◽  
Vol 264 (1) ◽  
pp. G74-G80 ◽  
Author(s):  
T. Frieling ◽  
H. J. Cooke ◽  
J. D. Wood
Keyword(s):  
Guinea Pig ◽  
Action Potentials ◽  
Acetylcholine Release ◽  
Input Resistance ◽  
Distal Colon ◽  
Intracellular Microelectrodes ◽  
Selective Agonists ◽  
Nicotinic Synapses

Intracellular microelectrodes were used to investigate the actions of histamine in the submucous plexus of the distal colon of the guinea pig. Three effects resulted from application of histamine to submucous neurons. The first was membrane depolarization associated with increased input resistance and augmented excitability. The second was presynaptic suppression of acetylcholine release at nicotinic synapses. The third occurred during long-term application and consisted of recurrent trains of action potentials associated with periodic depolarization of membrane potential. Pharmacological analysis, with selective agonists and antagonists, suggested mediation of the first and third response by postsynaptic histamine H2 receptors. The second response was mediated by presynaptic histamine H3 receptors. These actions of histamine represent a mechanism for neuroimmune signaling between mucosal mast cells and submucous neurons in gastrointestinal type 1 hypersensitivity reactions to allergens.

Thyrotropin-releasing hormone (TRH) depolarizes a subset of inspiratory neurons in the newborn mouse brain stem in vitro

1996 ◽  
Vol 75 (2) ◽  
pp. 811-819 ◽  
Author(s):  
J. C. Rekling ◽  
J. Champagnat ◽  
M. Denavit-Saubie
Keyword(s):  
Membrane Potential ◽  
Brain Stem ◽  
Respiratory Rhythm ◽  
Input Resistance ◽  
Newborn Mouse ◽  
Hypoglossal Motoneurons ◽  
Inspiratory Neurons ◽  
Type 3

1. To extend the classification of respiratory neurons based on active membrane properties and discharge patterns to include responses to respiratory modulators, we have studied the effect of thyrotropin-releasing hormone (TRH, 1-5 microM) on the spontaneous respiratory-related neural activity in a thick brain stem slice preparation from the newborn mouse. The action of TRH on the respiratory output from the slice was investigated by recordings from the XII nerve. Cellular responses to TRH were investigated using whole cell recordings from hypoglossal motoneurons and three types of inspiratory neurons located in the rostral ventrolateral part of the slice. 2. Bath-applied TRH (1 microM) decreased the time between inspiratory discharges recorded on the XII nerve from 12.3 +/- 3.3 s to 4.9 +/- 1.1 s (n = 28; means +/- SD), i.e., caused an approximate threefold increase in the respiratory frequency. The coefficient of variation of the time between the inspiratory discharges decreased by one-half. Thus the respiratory output became more stable in response to TRH. The duration of the inspiratory discharges increased from 474 +/- 108 ms to 679 +/- 114 ms, and the amplitude decreased by 24%. An increase in the interdischarge noise on the XII nerve was recorded in the early phase of the TRH application. 3. Anatomically identified hypoglossal motoneurons (7 cells) responded to bath applied TRH with a depolarization eliciting spikes between the inspiratory potentials. The depolarization was accompanied by an increase in spontaneous excitatory synaptic activity that disappeared late during the TRH application. The duration of the inspiratory potentials was increased, indicating that the hypoglossal motoneurons received a longer duration synaptic input from the respiratory rhythm generator. 4. Type-1 inspiratory neurons showed a prolonged depolarization (3 cells), a transient depolarization (2 cells), or no change in membrane potential (2 cells) during 10 min of continued superfusion with a TRH-containing solution. The duration of the inspiratory potentials was increased during the TRH superfusion. With tetrodoxin (TTX, 1 microM) present in the superfusing solution TRH induced a prolonged depolarization (3 cells) or a transient depolarization (1 cell), demonstrating that type-1 inspiratory neurons are depolarized postsynaptically by TRH. The input resistance was not changed during the depolarizing response to TRH. 5. Type-2 inspiratory neurons showed a transient depolarization (7 cells) in response to bath-applied TRH. The duration of the inspiratory potentials was increased markedly during TRH. The transient depolarization was not the result of a postsynaptic action of TRH, because type-2 neurons (9 cells) showed no depolarization to TRH with TTX present in the superfusing solution. 6. Type-3 inspiratory neurons showed a transient depolarization (4 cells) with a partial recovery of the membrane potential late during the TRH application. The duration of the inspiratory potentials increased markedly during TRH. Four cells showed a transient depolarization with an increase in input resistance during TRH with TTX present in the superfusing solution. Thus type-3 neurons are depolarized postsynaptically by TRH. 7. We conclude that TRH increases the frequency of the respiratory rhythm in newborn mice through an action at the level of the brain stem.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphology of electrophysiologically identified myenteric neurons in the guinea pig rectum

1992 ◽  
Vol 262 (3) ◽  
pp. G545-G552 ◽  
Author(s):  
K. Tamura
Keyword(s):  
Guinea Pig ◽  
Circular Muscle ◽  
Type I ◽  
Type Ii ◽  
Fiber Tracts ◽  
Single Spike ◽  
Type 3 ◽  
Dogiel Type Ii

Dye-filled microelectrodes were used to investigate relations between morphology and electrophysiological behavior of neurons in the myenteric plexus of the guinea pig rectum. The neurons were divided into two general classes on the basis of morphology. The first class had smooth ovoid somas with multiple long processes that exited the ganglion in several different fiber tracts and fit the description of Dogiel type II neurons. Neurons of the second class had a single long process that exited the ganglion in a fiber tract and sometimes projected to the circular muscle. Neurons of the second class were subdivided into three groups. One of these had short club-shaped dendrites like Dogiel type I neurons. Another had short tapering filamentous processes. Neurons with a single long neurite that could not be classified made up the third group. AH/type 2 electrophysiological behavior was found in both general classes of neurons. S/type 1 electrophysiological behavior occurred only in neurons of the general class with a single long neurite. Type 3 electrical behavior, characterized by robust fast synaptic input in inexcitable neurons, was found only in the cells defined by a single long neurite. Single-spike neurons behaved electrophysiologically like AH/type 2 neurons without long-lasting hyperpolarizing afterpotentials. This behavior was limited to the class of neurons characterized morphologically by a single long neurite.

Electrical behavior of myenteric neurons in guinea pig distal colon

1988 ◽  
Vol 254 (4) ◽  
pp. G522-G530 ◽  
Author(s):  
P. R. Wade ◽  
J. D. Wood
Keyword(s):  
Guinea Pig ◽  
Action Potentials ◽  
Distal Colon ◽  
Electrical Behavior ◽  
Myenteric Neurons ◽  
Single Action ◽  
Current Pulses

Intracellular recording was used in vitro to analyze electrophysiological properties of neurons in myenteric ganglia of guinea pig distal colon. The neurons were classified into six types based on their electrical behavior. Type 1 colonic neurons discharged action potentials throughout depolarizing current pulses and were otherwise similar to S/type 1 neurons found in the guinea pig small bowel. The second type had passive and active electrical properties similar to those of AH/type 2 myenteric neurons of the small intestine. These cells discharged only a single spike at the onset of depolarizing current pulses, and the spikes were followed by long-lasting hyperpolarizing afterpotentials. Excitability of the type 2 neurons was enhanced in the presence of elevated Mg2+ and reduced Ca2+, and the spikes were unaffected by tetrodotoxin. Type 3 colonic neurons showed fast synaptic potentials but did not generate action potentials. The majority of neurons were referred to as type 2 colonic neurons. Type 4 neurons discharged single action potentials only at the onset of depolarizing current pulses, and the spikes were not followed by prolonged hyperpolarizing afterpotentials. Unlike type 2 neurons, excitability remained unchanged in the presence of reduced extracellular Ca2+ and elevated Mg2+. Action potentials of type 4 neurons were suppressed or abolished by tetrodotoxin. A group of spontaneously active neurons was classified as type 5 colonic neurons. Type 6 cells were inexcitable and assumed to be glial cells.

FUNCTIONAL STATUS AND ADAPTIVE POTENTIAL IN FOREIGN STUDENTS WITH DIFFERENT TYPES OF VEGETATIVE REGULATION DURING TUITION

2020 ◽  
pp. 118-126
Author(s):  
A.M. Satarkulova
Keyword(s):  
Heart Rate ◽  
Foreign Students ◽  
Autonomic Regulation ◽  
The Body ◽  
Functional Changes ◽  
Different Types ◽  
Type 3 ◽  
Adaptive Abilities

The assessment and dynamic control over students’ status is a very important task. It allows timely detection of prenosological status prior to pathology and health maintenance in students. The objective of the paper is to assess the adaptive abilities of the body, to analyze changes in heart rate variability indicators in students with various types of autonomic regulation, to identify prenosological status and precursory pathological symptoms. Materials and Methods. The study enrolled 302 students from India, aged 21.54±1.43. Programming complex «Psychophysiologist» was used to register the main HRV parameters within 5 minutes. Health status was evaluated according to the index of functional changes and the scale of functional states. Results. N.I. Shlyk (2009) distinguished two groups of students with different types of autonomic regulation: type 1 (53 %) with moderate and type 2 (5 %) with marked characteristics of central regulation profile, type 3 (35 %) with moderate and type 4 (7 %) with marked characteristics of autonomous regulation profile. Main parameters of HRV and adaptation potential were defined for each student.All the parameters characterized functional and health status. Conclusions. It was shown that 82 % of trial subjects (type 1), 53 % (type 2), 94 % (type 3) and 95 % (type 4) demonstrated satisfactory adaptation and their physiological processes were at an optimal level. 18 % of students (type 1) demonstrated reduced adaptive abilities of the body. Moreover, they were under moderate stress. 47 % of subjects (type 2) were also under a significant stress, which was proven by excessively high SI, low SDNN and TP, and an increased index of functional changes. 5 % of students (type 4) revealed dysfunctional characteristics in the heart rhythm, peculiar to pathology. Keywords: foreign students, heart rate variability, types of autonomic regulation, adaptation potential, functional status. Оценка состояния студентов и динамический контроль за ним является важной задачей, поскольку позволяет своевременно выявлять у студентов донозологические состояния, предшествующие патологии, и способствовать сохранению здоровья. Цель. Оценка адаптивных возможностей организма, анализ изменений показателей вариабельности сердечного ритма у студентов с различными типами вегетативной регуляции, выявление донозологических состояний и ранних признаков патологии. Материалы и методы. В исследовании участвовало 302 студента в возрасте 21,54+1,43 года из Индии. Регистрировались основные параметры ВСР в течение 5 мин с использованием программно-аппаратного комплекса «Психофизиолог». Состояние и уровень здоровья оценивались по индексу функциональных изменений и шкале функциональных состояний. Результаты. По способу, предложенному Н.И. Шлык, выделены группы студентов с различными типами вегетативной регуляции: I (53 %) и II типы (5 %) – с умеренным и выраженным преобладанием центрального контура регуляции соответственно, III (35 %) и IV типы (7 %) – с умеренным и выраженным преобладанием автономного контура регуляции соответственно. У каждого из студентов определены основные параметры ВСР и адаптационного потенциала, характеризующие функциональное состояние и уровень здоровья. Выводы. Показано, что для 82 % обследуемых с I типом, 53 % со II типом, 94 % c III типом и 95 % с IV типом регуляции характерно состояние удовлетворительной адаптации, физиологические процессы сохраняются на оптимальном уровне. В группе студентов I типа у 18 % студентов адаптивные возможности организма снижены, выявлено состояние умеренного напряжения. У 47 % обследуемых II типа также зафиксировано состояние резко выраженного напряжения, индикатором которого является чрезмерно высокое значение SI, низкие величины SDNN и ТP, повышенное значение индекса функциональных изменений. В группе студентов с IV типом у 5 % учащихсяв регуляции ритма сердца выявлены дисфункциональные признаки, характерные для патологии. Ключевые слова: иностранные студенты, вариабельность сердечного ритма, типы вегетативной регуляции, адаптационный потенциал, функциональное состояние.

POLIOMYELITIS IN CANADIAN ESKIMOS: LABORATORY STUDIES. V. TYPE 1 AND TYPE 3 POLIOMYELITIS ANTIBODY LEVELS IN BAFFIN ISLAND ESKIMOS

1954 ◽  
Vol 32 (1) ◽  
pp. 119-125
Author(s):  
W. Wood ◽  
Eina M. Clark ◽  
F. T. Shimada ◽  
A. J. Rhodes
Keyword(s):  
Medical Records ◽  
Baffin Island ◽  
Tissue Cultures ◽  
Laboratory Studies ◽  
Poliomyelitis Virus ◽  
Antibody Titers ◽  
Antibody Levels ◽  
Type 3

Studies on the basic immunology of poliomyelitis in Canadian Eskimos have been continued. Some 87 sera collected from Eskimos at Pangnirtung, Baffin Island, have been examined for the presence of Type 1 and Type 3 poliomyelitis antibody by quantitative tests in tissue cultures. The same sera were previously examined for Type 2 antibody by quantitative tests in mice. The results of the three determinations are now presented together for comparison. These sera came from Eskimos aged 2 to 72 years of age. None of the Eskimos showed any evidence of paralysis. Examination of the medical records did not suggest that any paralytic disease had been present in this part of Baffin Island. Very few of the sera showed the presence of poliomyelitis antibody; thus, Type 1 antibody was demonstrated in the sera of 8%, Type 2 antibody in the sera of 9%, and Type 3 antibody in the sera of 14%. No significant number of Eskimos below the age of 45 years had acquired poliomyelitis antibody. The antibody titers mostly ranged between 10−1.0 and 10−2.0, and were significantly lower than the titers customarily found in recently paralyzed cases. These findings suggest that poliomyelitis infection occurred in Pangnirtung Eskimos many years before the date on which the samples were taken (1951). These results point to the worldwide prevalence of the three types of poliomyelitis virus.

Toward Personalized Treatment for Patients with Low von Willebrand Factor and Quantitative von Willebrand Disease

2021 ◽  
Vol 47 (02) ◽  
pp. 192-200
Author(s):  
James S. O'Donnell
Keyword(s):  
Von Willebrand Factor ◽  
Bleeding Risk ◽  
Von Willebrand Disease ◽  
Personalized Treatment ◽  
Treatment Plans ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

AbstractThe biological mechanisms involved in the pathogenesis of type 2 and type 3 von Willebrand disease (VWD) have been studied extensively. In contrast, although accounting for the majority of VWD cases, the pathobiology underlying partial quantitative VWD has remained somewhat elusive. However, important insights have been attained following several recent cohort studies that have investigated mechanisms in patients with type 1 VWD and low von Willebrand factor (VWF), respectively. These studies have demonstrated that reduced plasma VWF levels may result from either (1) decreased VWF biosynthesis and/or secretion in endothelial cells and (2) pathological increased VWF clearance. In addition, it has become clear that some patients with only mild to moderate reductions in plasma VWF levels in the 30 to 50 IU/dL range may have significant bleeding phenotypes. Importantly in these low VWF patients, bleeding risk fails to correlate with plasma VWF levels and inheritance is typically independent of the VWF gene. Although plasma VWF levels may increase to > 50 IU/dL with progressive aging or pregnancy in these subjects, emerging data suggest that this apparent normalization in VWF levels does not necessarily equate to a complete correction in bleeding phenotype in patients with partial quantitative VWD. In this review, these recent advances in our understanding of quantitative VWD pathogenesis are discussed. Furthermore, the translational implications of these emerging findings are considered, particularly with respect to designing personalized treatment plans for VWD patients undergoing elective procedures.

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