Open AccessChronic atropine administration diminishes the contribution of vasoactive intestinal polypeptide to heart rate regulation
Author(s) -
Jitka Kuncová,
S Faitová,
J Capouch,
Milan Štengl,
Jana Slavı́ková
Publication year - 2008
Publication title -
physiological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.647
H-Index - 70
eISSN - 1802-9973
pISSN - 0862-8408
DOI - 10.33549/physiolres.931350
Subject(s) - atropine , vasoactive intestinal peptide , stimulation , chronotropic , vagus nerve stimulation , heart rate , medicine , phentolamine , endocrinology , vagus nerve , receptor , neuropeptide , blood pressure
Vasoactive intestinal polypeptide (VIP) is implicated in themodulation of vagal effects on the heart rate. In this study, theimpact of acute and chronic atropine administration on VIP levelsin rat heart atria was investigated in relation to heart rate in thecourse of vagus nerves stimulation. Anaesthetised control andatropinised (10 mg/kg/day for 10 days) rats pretreated withmetipranolol and phentolamine that were either given or not asingle dose of atropine were subjected to bilateral vagus nervestimulation (30 min: 0.7 mA, 20 Hz, 0.2 ms). VIP concentrationsin the atria were determined after each stimulation protocol. Incontrol rats with or without single atropine administration, theheart rate upon vagal stimulation was higher than in atropinisedanimals with or without single atropine dose, respectively. VIPconcentrations in the control atria were significantly decreasedafter the stimulation; the decrease was comparable both in theabsence and presence of a single dose of atropine. Compared tocontrols, VIP levels were significantly decreased after chronicatropine treatment and they were not further reduced by vagalstimulation and single atropine administration. Administration ofVIP antagonist completely abolished the differences in the heartrate upon vagal stimulation between control and atropinisedgroups. In conclusion, the data indicate that chronic atropineadministration affects VIP synthesis in rat heart atria andconsequently it modifies the heart rate regulation.