TY - JOUR
T1 - Mode of action of ATP on propulsive activity in rabbit colon
AU - Tonini, Marcello
AU - Onori, Luciano
AU - Lecchini, Sergio
AU - Frigo, Gianmario
AU - Perucca, Emilio
AU - Crema, Antonio
PY - 1982/8/13
Y1 - 1982/8/13
N2 - ATP induced a concentration-dependent reduction of the velocity of propulsion in isolated segments of rabbit colon as assessed by the aboral displacement of an intraluminal rubber balloon, and delayed the onset of the propulsive wave. ATP depressed both the reflex contraction of the circular coat above the distended balloon and the response of the circular muscle to transmural (cholinergic) stimulation. On the contrary, ATP (up to 200 μM), while causing relaxation of the circular muscle, had no effect on either the muscular contractile induced by carbachol and histamine or the non-adrenergic inhibitory responses elicited by electrical stimulation and by radial distension of the gut wall. Within the concentration range used (10-200 μM), ATP concentration-depression curves Theophylline, however, had no influence on either the direct inhibitory action of ATP on circular smooth muscle or the non-adrenergic relaxation in response to electrical stimulation. These data are consistent with the concept that at least two populations of purinergic receptors are present in intestinal tissue. Those populations located presynaptically, unlike those located postsynaptically, are blocked by theophylline. Since the contractile machinery does not appear to be affected by ATP concentrations up to 200 μM, the mechanism by which ATP impairs propulsive activity is probably dependent on activation of presynaptic purinergic receptors located on the nervous pathways subserving the wave of contraction, without having any appreciable influence on descending inhibition.
AB - ATP induced a concentration-dependent reduction of the velocity of propulsion in isolated segments of rabbit colon as assessed by the aboral displacement of an intraluminal rubber balloon, and delayed the onset of the propulsive wave. ATP depressed both the reflex contraction of the circular coat above the distended balloon and the response of the circular muscle to transmural (cholinergic) stimulation. On the contrary, ATP (up to 200 μM), while causing relaxation of the circular muscle, had no effect on either the muscular contractile induced by carbachol and histamine or the non-adrenergic inhibitory responses elicited by electrical stimulation and by radial distension of the gut wall. Within the concentration range used (10-200 μM), ATP concentration-depression curves Theophylline, however, had no influence on either the direct inhibitory action of ATP on circular smooth muscle or the non-adrenergic relaxation in response to electrical stimulation. These data are consistent with the concept that at least two populations of purinergic receptors are present in intestinal tissue. Those populations located presynaptically, unlike those located postsynaptically, are blocked by theophylline. Since the contractile machinery does not appear to be affected by ATP concentrations up to 200 μM, the mechanism by which ATP impairs propulsive activity is probably dependent on activation of presynaptic purinergic receptors located on the nervous pathways subserving the wave of contraction, without having any appreciable influence on descending inhibition.
KW - ATP
KW - Propulsion
KW - Rabbit colon
KW - Theophylline
KW - Transmural stimulation
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U2 - 10.1016/0014-2999(82)90548-9
DO - 10.1016/0014-2999(82)90548-9
M3 - Article
C2 - 7128678
AN - SCOPUS:0019985156
VL - 82
SP - 21
EP - 28
JO - European Journal of Pharmacology
JF - European Journal of Pharmacology
SN - 0014-2999
IS - 1-2
ER -