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.

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.

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.

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.

Taste responses of cortical neurons in freely ingesting rats

1989 ◽  
Vol 61 (6) ◽  
pp. 1244-1258 ◽  
Author(s):  
T. Yamamoto ◽  
R. Matsuo ◽  
Y. Kiyomitsu ◽  
R. Kitamura
Keyword(s):  
Cortical Neurons ◽  
Correlation Coefficients ◽  
Entropy Measure ◽  
Response Patterns ◽  
Gustatory System ◽  
Basic Taste ◽  
Quinine Hydrochloride ◽  
Excitatory Responses

1. Activities of 35 taste-responsive neurons in the cortical gustatory area were recorded with chronically implanted fine wires in freely ingesting Wistar rats. Quantitative analyses were performed on responses to distilled water, food solution, and four taste stimuli: sucrose, NaCl, HCl, and quinine hydrochloride. 2. Taste-responsive neurons were classified into type-1 and type-2 groups according to the response patterns to licking of the six taste stimuli. Type-1 neurons (n = 29) responded in excitatory or inhibitory directions to one or more of the taste stimuli. Type-2 neurons (n = 6) showed responses in different directions depending upon palatability of the liquids to rats: neurons showing excitatory (or inhibitory) responses to palatable stimuli exhibited inhibitory (or excitatory) responses to unpalatable stimuli. 3. Correlation coefficients of responses to pairs of stimuli across neurons suggested that palatable stimuli (water, food solution, sucrose, and NaCl) and unpalatable stimuli (HCl and quinine) elicited reciprocal (excitatory vs. inhibitory) responses in type-2 neurons, whereas type-1 neurons showed positively correlated responses to specific combinations of stimuli such as food solution and NaCl, sucrose and HCl, NaCl and quinine, and HCl and quinine. 4. A tendency toward equalization of effectiveness in eliciting responses among the four basic taste stimuli was detected on the cortex. The ratios of mean evoked responses in 29 type-1 neurons in comparison with spontaneous rate (4.4 spikes/s) were 1.7, 1.9, 1.8, and 1.9 for sucrose, NaCl, HCl, and quinine, respectively. 5. The breadth of responsiveness to the four basic taste stimuli was quantified by means of the entropy measure introduced by Smith and Travers (33). The mean entropy value was 0.540 for 29 type-1 neurons, which was similar to 0.588 previously reported for rat chorda tympani fibers, suggesting that breadth of tuning is not more narrowly tuned in a higher level of the gustatory system in the rat. 6. Convergent inputs of other sensory modalities were detected exclusively in type-1 neurons. Thirteen (45%) of 29 type-1 neurons also responded to cold and/or warm water, but none of 6 type-2 neurons responded to thermal stimuli. Two (7%) of 29 type-1 neurons responded to almond and acetic acid odors, but the 6 type-2 neurons did not. Two (13%) of 16 type-1 neurons responded to interperitoneal injection of LiCl, which is known to induce gastrointestinal disorders, with a latency of approximately 5 min, but 4 type-2 neurons tested were not responsive to this stimulation.(ABSTRACT TRUNCATED AT 400 WORDS)

Glial Cells and Pro-inflammatory Cytokines as Shared Neurobiological Bases for Chronic Pain and Psychiatric Disorders

2020 ◽  
pp. 27-49
Author(s):  
Judith A. Strong ◽  
Sang Won Jeon ◽  
Jun-Ming Zhang ◽  
Yong-Ku Kim
Keyword(s):  
Chronic Pain ◽  
Nervous System ◽  
Psychiatric Disorders ◽  
Inflammatory Cytokines ◽  
Glial Cells ◽  
Neuronal Excitability ◽  
Pro Inflammatory Cytokines

This chapter reviews the roles of cytokines and glial cells in chronic pain and in psychiatric disorders, especially depression. One important role of cytokines is in communicating between activated glia and neurons, at all levels of the nervous system. This process of neuroinflammation plays important roles in pain and depression. Cytokines may also directly regulate neuronal excitability. Many cytokines have been implicated in both pain and psychiatric disorders, including interleukin-1β‎ (IL-1β‎), tumor necrosis factor-α‎, and IL-6. More generally, an imbalance between type 1, pro-inflammatory cytokines and type 2, anti-inflammatory cytokines has been implicated in both pain and psychiatric disorders. Activation of the sympathetic nervous system can contribute to both pain and psychiatric disorders, in part through its actions on inflammation and the cytokine profile.

Synaptic behavior of myenteric neurons in guinea pig distal colon

1988 ◽  
Vol 255 (2) ◽  
pp. G184-G190 ◽  
Author(s):  
P. R. Wade ◽  
J. D. Wood
Keyword(s):  
Guinea Pig ◽  
Input Resistance ◽  
Distal Colon ◽  
Bathing Medium ◽  
Myenteric Neurons ◽  
Fiber Tracts ◽  
Slow Rise ◽  
Domain 3 ◽  
Myenteric Ganglia

Intracellular recording methods were used in vitro to analyze the synaptic behavior of neurons in myenteric ganglia of guinea pig distal colon. Fast excitatory postsynaptic potentials (EPSPs) were observed in a variety of types of colonic neurons. Both spontaneous and stimulus-evoked EPSPs were abolished or suppressed by addition of hexamethonium, tetrodotoxin, or elevation of Mg2+ and reduction of Ca2+ in the bathing medium. Individual neurons usually received inputs from several fiber tracts and multiple EPSPs were sometimes evoked by electrical stimulation of single-fiber tracts. Stimulus-evoked fast EPSPs were always of greater amplitude, longer duration, and longer decay time than were spontaneous fast EPSPs in the same neurons. No rundown of the fast EPSPs occurred during prolonged stimulation at frequencies up to 10 Hz. Repetitive stimulation evoked slow depolarizing potentials (slow EPSPs) in 25% of the neurons. Characteristics of the slow EPSPs were 1) slow rise times, 2) duration in the seconds time domain, 3) enhanced excitability, 4) increased input resistance, and 5) reduction of hyperpolarizing after-potentials. In general, the variety of synaptic potentials and the properties of the events were the same as found in myenteric neurons of the guinea pig small bowel. Compared with synaptic behavior of small intestinal myenteric neurons, the notable differences were absence of the rundown phenomenon for fast EPSPs in the colonic neurons and a greater incidence of spontaneously occurring fast EPSPs.

An intracellular study of myenteric neurons in the mouse colon

1986 ◽  
Vol 55 (6) ◽  
pp. 1395-1406 ◽  
Author(s):  
K. Furukawa ◽  
G. S. Taylor ◽  
R. A. Bywater
Keyword(s):  
Small Intestine ◽  
Guinea Pig ◽  
Nerve Stimulation ◽  
Circular Muscle ◽  
Input Resistance ◽  
Synaptic Activity ◽  
Myenteric Neurons ◽  
Mouse Colon ◽  
Long Latency ◽  
Wide Range

Intracellular recordings have been made in vitro from the myenteric neurons of the distal colon of normal littermates of the piebald-lethal mouse. Out of a total of 90 neurons, 82 were classified as S/type 1 cells and 8 as AH/type 2 cells. Seventy-eight out of 82 S cells showed spontaneous fast excitatory postsynaptic potentials (EPSPs) sensitive to d-tubocurarine (dTC, 280 microM), and 22 S cells showed spontaneous action potentials (APs). Six S cells and 1 AH cell showed spontaneous nonnicotinic slow depolarizations associated with an increase in the input resistance of the cells; during the spontaneous slow depolarization in the S cells there was an increase in the frequency of nicotinic fast EPSPs and APs. Three S cells showed spontaneously occurring regular oscillations of the membrane potential (approximately mV in amplitude and approximately 4/min). Transmural nerve stimulation produced fast EPSPs with a wide range of latencies (3 ms to 20 s) in S cells; the fast EPSPs were blocked by dTC (280 microM) or solutions containing low Ca2+ (0.25 mM) and high Mg2+ (12 mM) but not by atropine (ATR, 14 microM). Single or repetitive transmural stimulation produced slow EPSPs in 24 S cells and 3 AH cells; these were not blocked by dTC (280 microM) nor ATR (14 microM). During the slow EPSPs there was an increase in the input resistance of the cells. In those S cells that showed slow EPSPs there were many long-latency fast EPSPs; long-latency fast EPSPs were also observed in 11 other S cells that did not show a slow EPSP following repetitive transmural nerve stimulation. Long-latency fast EPSPs may be related to the firing of other neurons during their slow EPSPs. The myenteric neurons in the mouse colon have similar properties to the myenteric neurons in the guinea pig small intestine. However, the colonic myenteric neurons show more ongoing synaptic activity and more prolonged activity after nerve stimulation than myenteric neurons in the guinea pig small intestine. This activity may be due to regional differences, species differences, or preparation differences (in this study the myenteric plexus was adherent to the underlying circular muscle layer).

scholarly journals Differences in attachment between herpes simplex type 1 and type 2 viruses to neurons and glial cells

1980 ◽  
Vol 28 (3) ◽  
pp. 675-680
Author(s):  
A Vahlne ◽  
B Svennerholm ◽  
M Sandberg ◽  
A Hamberger ◽  
E Lycke
Keyword(s):  
Herpes Simplex ◽  
Glial Cells ◽  
Binding Capacity ◽  
No Adsorption ◽  
Virus Binding ◽  
Simplex Virus ◽  
Astrocytic Glia ◽  
Hsv 1

Fractions of nerve cell perikarya, synaptosomes, and astrocytic glia were prepared from human, monkey , rabbit, rat, and mouse brain tissue. The herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) binding capacity of these fractions was studied. Pretreatment of fractions with one type of HSV and the subsequent testing of adsorption of homotypic and heterotypic virus ws employed to reveal type selectivity of virus binding receptors. A higher density of HSV-1 than of HSV-2 selective receptors was found on synaptosomes and glial cells, except with mouse-derived preparations. Synaptosomal and glial cell preparations of mouse brains adsorbed both types of HSV well. Little or no adsorption was observed with HSV-1 and HSV-2 to neuronal perikarya. The type selectivity of HSV binding receptors on brain cells ws demonstrated on preparations of human synaptosomes and mouse glial cells. Some possible implications of the observations on the HSV infection of the nervous system are discussed.

Synaptic inputs to morphologically identified myenteric neurons in guinea pig rectum from pelvic nerves

1997 ◽  
Vol 273 (1) ◽  
pp. G49-G55 ◽  
Author(s):  
K. Tamura
Keyword(s):  
Morphological Characteristics ◽  
Pelvic Nerve ◽  
Low Frequencies ◽  
Myenteric Neurons ◽  
Synaptic Inputs ◽  
Pelvic Nerves ◽  
Single Spike ◽  
Stimulation Of

Neurobiotin-filled microelectrodes were used to investigate electrical and synaptic behavior and morphological characteristics of rectal myenteric neurons that received synaptic inputs from the pelvic nerves. Stimulation of the pelvic nerve at low frequencies (< 3.3 Hz) evoked nicotinic fast excitatory postsynaptic potentials (fast EPSPs) in 45.3% of rectal neurons. Pelvic fast EPSPs were found in S/type 1, AH/type 2, type 3, or single-spike neurons that had a single long process preferentially projecting in the orad direction. Stimulation of the pelvic nerve at higher frequencies (5–20 Hz) elicited slow membrane excitation in 13.9% of the neurons. They were either AH/type 2 neurons with Dogiel II morphology or S/type 1 neurons with a single long process. Hexamethonium (100 microM) blocked pelvic fast EPSPs more quickly than those evoked by fiber tract stimulation but did not affect slow excitatory response. The results suggested the presence of more than one nicotinic-cholinergic synapse in the pelvic nerve pathway and the possible release of a noncholinergic excitatory substance from the afferent nerve terminals. It is possible that a subpopulation of rectal neurons, which receive a fast EPSP and have a single long process that projects in the orad direction, might be interneurons that mediate the defecation reflex.

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