Innervation of human epicardial coronary veins: immunohistochemistry and vasomotility.
OBJECTIVE
The aim was to investigate the innervation and vasomotor responses to classical and putative transmitters of the coronary venous bed.


METHODS
The innervation of human epicardial coronary veins was investigated using acetylcholinesterase histochemistry and immunofluorescence staining, together with antisera against the general neuronal marker protein gene product 9.5 (PGP 9.5), the catecholamine synthesising enzyme tyrosine hydroxylase, and neuropeptides [neuropeptide Y, vasoactive intestinal peptide (VIP), substance P, and calcitonin gene related peptide (CGRP)]. The vasomotor responses to noradrenaline, acetylcholine, neuropeptide Y, substance P, human alpha calcitonin gene related peptide (alpha CGRP), and VIP were tested on isolated circular human epicardial coronary vein segments.


RESULTS
A network of nerve fibres was shown in the major epicardial coronary veins by means of an antiserum to PGP 9.5. The majority of the perivascular nerve fibres possessed neuropeptide Y and tyrosine hydroxylase immunoreactivity. Only a few nerve fibres displayed substance P, CGRP, and VIP immunoreactivity and acetylcholinesterase activity. Noradrenaline and acetylcholine induced powerful contractions of all the tested segments, whereas no contraction was induced by neuropeptide Y, alpha CGRP, substance P, or VIP. All segments precontracted with U46619 responded with potent relaxation to alpha CGRP, substance P, and VIP, whereas noradrenaline and acetylcholine only in low concentrations induced weak relaxation of a few of the segments. No relaxation was induced by neuropeptide Y.


CONCLUSIONS
This is the first study to demonstrate comprehensively the perivascular innervation of human coronary veins and corresponding vasomotor effects, suggesting a role in regulation of the coronary venous circulation.
Saetrum Opgaard
O
O
Department of Internal Medicine, University Hospital of Lund, Sweden.
Gulbenkian
S
S
Bergdahl
A
A
Barroso
C P
CP
Andrade
N C
NC
Polak
J M
JM
Queiroz e Melo
J Q
JQ
Edvinsson
L
L
D000109:Acetylcholine / Q000494:pharmacology; D000328:Adult; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D003331:Coronary Vessels / Q000294:innervation*; D005455:Fluorescent Antibody Technique; D006651:Histocytochemistry; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D009478:Neuropeptide Y / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology; D014666:Vasomotor System / Q000187:drug effects*
D009478:Neuropeptide Y; D018377:Neurotransmitter Agents; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D015740:Calcitonin Gene-Related Peptide; D000109:Acetylcholine; D009638:Norepinephrine