Experiments were performed to determine the degree of overlap in the distribution of muscarinic receptors and cholinergic innervation of the rat heart. Localization of muscarinic receptors was determined by autoradiography with [3H]quinuclidinyl benzilate. Adjacent sections were stained for acetylcholinesterase to determine innervation. The distribution of muscarinic receptors and cholinergic innervation overlapped in cardiac parasympathetic ganglia, nodal tissue, His bundle-Purkinje system, vena cava and pulmonary veins. Cholinergic innervation to the right atrium was greater than to the left atrium while muscarinic receptor density was equal in the two atria. Innervation of the ventricles was confined primarily to the base of the right ventricle. A low density of muscarinic receptors was observed throughout the ventricles. Neither cholinergic innervation nor muscarinic receptors were detected in the pulmonary trunk, ascending aorta or cardiac valves. Muscarinic receptors and cholinergic innervation in the nodal regions, ventricular conduction system and myocardium probably mediate negative chronotropic, dromotropic and inotropic effects of vagal nerve stimulation. Muscarinic receptors at sites not containing cholinergic innervation may be associated with noradrenergic nerves of the myocardium.

Muscarinic ligand binding sites in fragments of rat hypothalamus and pituitary were studied using [3H]quinuclidinyl benzilate (QNB). In the hypothalamus, the highest amount of specific QNB binding was to n. paraventricularis and n. dorsomedialis. Specific QNB binding in other hypothalamic regions varied within a relatively narrow range. Fragments of whole pituitary also bound QNB but to a much smaller degree than brain. Pituitary binding of QNB was blocked by atropine but not by hexamethonium or d-tubocurarine. Within the pituitary, specific QNB binding to posterior pituitary was three times greater than to anterior pituitary. These findings are consistent with the operation of cholinergic mechanisms in hypothalamic and pituitary function.

The compound 3-quinuclidinyl benzylate (agent BZ) belongs to the group of incapacitating warfare agents with anticholinergic activity. Today, for its ability to induce functional cognitive impairment (i.e. coordination and memory disorders), the agent BZ is used mainly for scientific purposes in the study of Alzheimer's disease. Despite this fact, its pharmacokinetics has not been fully examined yet. In order to determine the agent BZ in biological material, LC-MS / MS method and sample preparation procedure for body fluids (plasma, bile) and tissues (brain, liver, kidneys) were developed, optimized and validated. The sample preparation procedure for body fluid employed solid phase extraction using a C18 column eluted with methanol and for body tissues it was precipitation with acetonitrile. The chromatographic separation was performed on Gemini NX-C18 reverse phase column (150 × 4.6 mm, 5 μm). The mobile phase consisted of a 10mM solution of ammonium acetate at pH 11 and methanol in a ratio of 30 : 70. Elution of the analytes was performed under isocratic elution. The total analysis time was 5 minutes. Mass spectrometric detection was performed by a linear ion trap using electrospray ionization. Sample preparation procedure and chromatographic analysis methods were successfully applied to real...