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BACKGROUND Subsets of myenteric neurons have been identified. To determine the proportional representation of neurons in each, it is necessary to relate the number of neurons in the subset to that of the complete set. Prior estimates of total numbers of neurons, obtained with many different markers, have varied widely. METHODS Markers were compared for(More)
The peristaltic reflex can be evoked in the absence of input from the CNS because the responsible neural pathways are intrinsic to the intestine. Mucosal enterochromaffin cells have been postulated to be pressure transducers, which activate the intrinsic sensory neurons that initiate the reflex by secreting 5-HT. All of the criteria necessary to establish(More)
Studies of the guinea pig small intestine have suggested that serotonin (5-HT) may be a mucosal transmitter that stimulates sensory nerves and initiates peristaltic and secretory reflexes. We tested the hypothesis that guinea pig villus epithelial cells are able to inactivate 5-HT because they express the same 5-HT transporter as serotonergic neurons. A(More)
The roles of 5-hydroxytryptamine3 (5-HT3), 5-HT4, and nicotinic receptors in the peristaltic reflex were investigated in isolated segments of guinea pig distal colon. The reflex assessed by measuring the propulsion of solid pellets, was affected neither by 5-HT3-selective antagonists (ondansetron granisetron) nor by 5-HT4-selective antagonists (SDZ-205-557,(More)
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(More)
The morphological and physiological characteristics of myenteric neurons in the guinea pig distal colon were determined using Lucifer yellow- or N-(2-aminoethyl) biotinamide-containing microelectrodes and intracellular recording and staining methods. The neurons in this study (n = 204) were classified on the basis of the shapes of their cell bodies and(More)
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,(More)
5-Hydroxytryptamine (5-HT) receptors have been analyzed and related to potential roles played by 5-HT in the physiology of the enteric nervous system (ENS). Three subtypes of 5-HT receptor--5-HT1P, 5-HT3, and 5-HT1A--have been found on enteric neurons. Receptors have been identified by intracellularly recording the electrical activity of enteric neurons and(More)
Two subtypes of excitatory 5-hydroxytryptamine (5-HT) receptor, 5-HT1P and 5-HT3, are found on type 2-AH neurons of the guinea pig myenteric plexus. The 5-HT1P receptor mediates a slow and the 5-HT3 receptor a fast depolarization of these cells, however, the role of these receptors in the physiology of the gut is unknown. Renzapride (BRL 24924), a(More)
The effects of anti-idiotypic antibodies (alpha-id) that recognize serotonin [5-hydroxytryptamine (5-HT)] receptors on myenteric neurons of the guinea pig small intestine were characterized electrophysiologically, and alpha-id binding sites were located immunocytochemically. Initial applications of the alpha-id mimicked each of three actions of 5-HT: a(More)