title: Effects of receptor blockers (methysergide, propranolol, phentolamine, yohimbine and prazosin) on desimipramine-induced pituitary hormone stimulation in humans--II. Prolactin.
abstract: In this report the effects of various receptor blockers on desimipramine (DMI)-induced prolactin (PRL) secretion in healthy male subjects are presented. Each trial consisted of two administrations: one of DMI i.v. alone and one of DMI i.v. in combination with the respective receptor blocker: methysergide (serotonin (5-HT) receptor blocker), propranolol (beta receptor blocker), phentolamine (alpha-1/alpha-2 receptor blocker), yohimbine (alpha-2 greater than alpha-1 receptor blocker), and prazosin (alpha-1 receptor blocker). Following administration of methysergide (12 mg p.o., n = 12), a significantly lower (p less than 0.01) DMI-induced PRL secretion compared to DMI alone in another group of subjects (n = 12) was observed. Combined administration with propranolol (15 mg i.v.) significantly enhanced the DMI-induced PRL secretion compared to DMI 50 mg i.v. alone (n = 18, incomplete block design) (p less than 0.01). Neither combined administration with phentolamine (60 mg i.v., n = 12), yohimbine (10 mg i.v., n = 6), nor prazosin (1 mg p.o., n = 12) significantly influenced the DMI-induced PRL secretion compared to DMI alone in the same subjects. The results of the present study, especially the inhibitory effect on DMI-induced PRL secretion of methysergide, indicate that the primarily noradrenaline (NA) and lesser serotonin (5-HT) reuptake inhibiting antidepressant DMI stimulates PRL secretion via 5-HT neurons. Furthermore, the significantly enhanced PRL release following combined administration of DMI and propranolol suggests that a noradrenergic inhibitory effect also may be involved in the transmission of the PRL stimulus.
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000187:drug effects; D002352:Carrier Proteins; D003891:Desipramine / Q000494:pharmacology*; D004347:Drug Interactions; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008784:Methysergide / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D010907:Pituitary Hormones / Q000378:metabolism*; D011224:Prazosin / Q000494:pharmacology; D011388:Prolactin / Q000378:metabolism*; D011433:Propranolol / Q000494:pharmacology; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D013997:Time Factors; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D001786:Blood Glucose; D002352:Carrier Proteins; D010907:Pituitary Hormones; D011955:Receptors, Drug; D017981:Receptors, Neurotransmitter; C036079:desipramine receptor; D015016:Yohimbine; D011388:Prolactin; D011433:Propranolol; D003891:Desipramine; D011224:Prazosin; D008784:Methysergide; D010646:Phentolamine