Selective autonomic blockade with propranolol, atropine, and combined atropine and propranolol was used to elucidate the role of the autonomic nervous system in the cardiovascular responses that occur during voluntary static exercise in conscious cats. Seven animals were operantly conditioned to hold a bar against a fixed resistance for a constant time of 15 seconds and were then placed on an e...

In humane, the parasympathetic nervous system predominates over the sympathetic nervous system in control of heart rate, but little is known about the relative influences of cholinergic and adrenergic tone on the electrophysiological properties of the ventricle and atrioventricular (AV) node. Thirteen subjects were studied using standard electrophysiological testing techniques in the control st...

Femomi blood flow and arterial pressure l-esponses to stimulation of the lumbar sympathetic chain at L3, L4 and L5 were compared with i-esponses to intm-arterial injections of 1-epinephrine and 1-norepinephrine before and after progressively increasing levels of adrenergic blockade, and after atropine. The vasoconstrictor i-esponses to nerve stimulation resembled most closely those caused by 1-...

The importance of vagal efferent signaling for the insulinotropic and glucagonostatic effects of glucagon-like peptide-1 (GLP-1) was investigated in a randomized single-blinded study. Healthy male participants (n = 10) received atropine to block vagal cholinergic transmission or saline infusions on separate occasions. At t = 15 min, plasma glucose was clamped at 6 mmol/l. GLP-1 was infused at a...

The basis of the vasodepressor response in patients with carotid sinus hypersensitivity (CSH) is unknown, and prevention of recurrent vasodepressor-induced hypotension in these patients has not been possible. In this study we assessed the effectiveness of atrioventricular sequential pacing and pharmacologic interventions in the prevention of carotid sinus massage (CSM)-induced vasodepressor res...

Many drugs used in anaesthesia have some potential fatal consequences; for example complete heart block and Q-Tc interval prolongation. Since the parasympathetic system in children is not fully developed, electrical transmission of the heart is not stable. Neostigmine is used in order to reverse neuromuscular block but it may also lead to prolongation of Q-Tc interval. We present a case of an 1...

To determine the role of cholinergic reflexes on pancreatic secretory response to food, we studied the effect of atropine on amylase secretion in response to the octapeptide of cholecystokinin (CCK8) and to intraintestinal oleate. Four studies were done in six healthy volunteers. The duodenal content was aspirated by a double lumen tube while synthetic secretin (41 pmol/kg/h) was infused as a b...

We recently identified hexamethonium-resistant peristalsis in the guinea pig colon. We showed that, following acute blockade of nicotinic receptors, peristalsis recovers, leading to normal propagation velocities of fecal pellets along the colon. This raises the fundamental question: what mechanisms underlie hexamethonium-resistant peristalsis? We investigated whether blockade of the major recep...

In order to assess the role of the autonomic system in the age differences in heart rate, propranolol 0.2 mg./kg. and atropine 30 micrograms/kg. were given to 103 infants and children during the course of heart catheterization. Mean control minute heart rate varied from 118 at age 1 year to 81 at age 16 years. Heart rate after drugs was termed intrinsic heart rate after Jose, and the mean varie...

OBJECTIVE To determine whether the nocturnal fall in plasma adrenaline is a cause of nocturnal asthma. DESIGN Double blind placebo controlled cross-over study. In the first experiment the nocturnal fall in plasma adrenaline at 4 am was corrected in 10 asthmatic subjects with an infusion of adrenaline after parasympathetic blockade with 30 micrograms/kg intravenous atropine. In the second expe...