title: Pituitary adenylate cyclase-activating polypeptide, helospectin, and vasoactive intestinal polypeptide in human corpus cavernosum.
abstract: 1. The distribution and effects of pituitary adenylate cyclase-activating polypeptide (PACAP-27 and -38), helospectin (Hel-1 and Hel-2), and vasoactive intestinal polypeptide (VIP), were investigated in isolated preparations of human corpus cavernosum (CC). 2. Immunohistochemistry revealed coinciding profiles of nerve structures that showed immunoreactivities for VIP and PACAP, and VIP and Hel. Confocal microscopy showed the co-existence of VIP- and PACAP-immunoreactivities, and VIP- and Hel-immunoreactivities in most (90%) varicose nerve structures. 3. As determined by radioimmunoassay, the amounts of VIP, PACAP-27, and PACAP-38 in the preparations were 61.7 +/- 11.6, 0.1 +/- 0.05, and 3.7 +/- 0.5 pmol g-1 wet weight of tissue (pmol g-1 wet wt.), respectively. In tissue from patients with diabetes, the content of VIP was lower (13.7 +/- 0.5 pmol g-1 wet wt.), whereas that of PACAP (-27 and -38) was unchanged. 4. Cyclic nucleotide levels were determined in preparations exposed to PACAP-27, PACAP-38, Hel-1, Hel-2, and VIP. All the peptides, but Hel-2, significantly increased the concentrations of cyclic AMP, whereas the levels of cyclic GMP were unchanged. 5. The peptides concentration-dependently relaxed noradrenaline-contracted preparations. The order of potency was VIP > PACAP 27 > Hel-1 > Hel-2 > PACAP-38. 6. Hel-1, VIP and PACAP-27 effectively counteracted electrically induced contractions. At 10(-6) M, the highest peptide concentration used, the inhibitory effects obtained reached 96 +/- 3%, 87 +/- 6%, and 80 +/- 3%, respectively. 7. The results suggest that PACAP and Hel-1 are co-localized with VIP in nerve structures within the human cavernous tissue, and that the peptides are effective relaxants of CC preparations in vitro. The role of the investigated peptides for penile erection remains to be established.
authors.affiliation: Department of Clinical Pharmacology, Lund University Hospital, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Hedlund
authors.forename: P
authors.initials: P
authors.lastname: Alm
authors.forename: P
authors.initials: P
authors.lastname: Ekström
authors.forename: J
authors.initials: J
authors.lastname: Fahrenkrug
authors.forename: J
authors.initials: J
authors.lastname: Hannibal
authors.forename: H
authors.initials: H
authors.lastname: Hedlund
authors.forename: B
authors.initials: B
authors.lastname: Larsson
authors.forename: K E
authors.initials: KE
authors.lastname: Andersson
mesh_terms: D000328:Adult; D000368:Aged; D000242:Cyclic AMP / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism; D004558:Electric Stimulation; D016650:Fluorescein-5-isothiocyanate; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D018613:Microscopy, Confocal; D008875:Middle Aged; D009126:Muscle Relaxation / Q000187:drug effects; D009479:Neuropeptides / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D010410:Penile Erection / Q000502:physiology; D010413:Penis / Q000378:metabolism* / Q000502:physiology*; D010455:Peptides / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism* / Q000494:pharmacology / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology
chemical_list: C495401:ADCYAP1 protein, human; D009479:Neuropeptides; D010455:Peptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D014662:Vasoconstrictor Agents; C091796:helospectin; D014660:Vasoactive Intestinal Peptide; D000242:Cyclic AMP; D006152:Cyclic GMP; D016650:Fluorescein-5-isothiocyanate; D009638:Norepinephrine