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Effects of interactions between interleukin‐1β and leptin on cat intestinal vagal mechanoreceptors
Author(s) -
Gaigé Stéphanie,
Abou Einate,
Abysique Anne,
Bouvier Michel
Publication year - 2004
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2003.054379
Subject(s) - leptin , excitatory postsynaptic potential , cholecystokinin , medicine , endocrinology , nodose ganglion , chemistry , vagus nerve , antagonist , receptor , stimulation , obesity
In a previous study, we established that leptin acts on chemosensitive intestinal vagal mechanoreceptors and that its excitatory effects are blocked by the endogenous interleukin‐1β receptor antagonist (Il‐1ra). To determine how interleukin‐1β (Il‐1β) is involved in the action of leptin, we studied the effects of this drug on the single vagal afferent activities of intestinal mechanoreceptors in anaesthetized cats. For this purpose, the activity of 34 intestinal vagal mechanoreceptors was recorded via glass microelectrodes implanted in the nodose ganglion. Il‐1β (1 μg) administered into the artery irrigating the upper part of the intestine activated both the 16 leptin‐activated units (type 1 units; P < 0.01 ) and the 12 leptin‐inhibited units (type 2 units; P < 0.001 ), but had no effect on the six leptin‐insensitive units. Cholecystokinin (CCK, 10 μg) induced an activatory response only in the two types of Il‐1β‐sensitive units. When Il‐1β was administered after CCK, its excitatory effects on type 1 units were enhanced, whereas the excitatory effects on type 2 units were abolished. Pre‐treatment with Il‐1ra (250 μg) blocked all the effects of Il‐1β and the excitatory effects of leptin on type 1 units, whereas it enhanced the inhibitory effects of leptin on type 2 units. It can therefore be concluded that (i) leptin acts on intestinal vagal mechanoreceptors via Il‐1β in the case of the type 1 units and independently of Il‐1β in the case of the type 2 units, and (ii) type 1 and type 2 units belong to two different populations of vagal afferents that transmit different information about ingestion or inflammation to the CNS, depending on the chemical environment.