Biomaterial Database

Effect of electrical stimulation of the ventromedial nucleus and the dorsomedial nucleus on the activity of tuberoinfundibular dopaminergic neurons. 1988

J W Gunnet, and K E Moore

Department of Pharmacology and Toxicology, Michigan State University, East Lansing.

Perikarya and terminals of tuberoinfundibular dopaminergic (TIDA) neurons are located in the arcuate nucleus (ARN) and in the median eminence (ME), respectively. Dopamine (DA) released from TIDA terminals in the ME inhibits prolactin secretion from the anterior pituitary. Anatomical studies have described the sources of afferents to ARN and ME, but not to TIDA neurons per se. The ventromedial nucleus (VMN) and the dorsomedial nucleus (DMN) of the hypothalamus project to ARN and ME and have a role in prolactin regulation. In the present study, VMN and DMN were investigated as possible sources of TIDA afferents. Alterations in the activity of TIDA neurons were estimated by measuring plasma concentrations of prolactin and the rates of DA synthesis (3,4-dihydroxyphenylalanine - DOPA - accumulation after administration of the decarboxylase inhibitor NSD 1015) and metabolism (concentrations of the DA metabolite 3,4-dihydroxyphenylacetic acid - DOPAC) in the ME following electrical stimulation of ARN, VMN, and DMN in ovariectomized female rats. Thirty minutes of bilateral stimulation of ARN or DMN increased DOPA accumulation in the ME; stimulation of the VMN had no effect. 5-Hydroxytryptamine synthesis in the ME was unaffected by stimulation of any region. Plasma prolactin levels declined during DMN stimulation, varying with the frequency and duration of the electrical stimulus. DA metabolism within TIDA neurons increased with DMN stimulation, as evidenced by increased DOPAC concentrations in the ME. In females whose basal TIDA activity has been increased by haloperidol treatment or decreased by bromocriptine treatment, DMN stimulation was still able to increase DOPA accumulation in the ME. The present data suggest the presence of stimulatory TIDA afferents originating from or passing through the DMN.

UI	MeSH Term	Description	Entries
D007033	Hypothalamus, Middle	Middle portion of the hypothalamus containing the arcuate, dorsomedial, ventromedial nuclei, the TUBER CINEREUM and the PITUITARY GLAND.	Hypothalamus, Medial,Intermediate Hypothalamic Region,Hypothalamic Region, Intermediate,Hypothalamic Regions, Intermediate,Intermediate Hypothalamic Regions,Medial Hypothalamus,Middle Hypothalamus,Region, Intermediate Hypothalamic,Regions, Intermediate Hypothalamic
D008473	Median Eminence	Raised area at the infundibular region of the HYPOTHALAMUS at the floor of the BRAIN, ventral to the THIRD VENTRICLE and adjacent to the ARCUATE NUCLEUS OF HYPOTHALAMUS. It contains the terminals of hypothalamic neurons and the capillary network of hypophyseal portal system, thus serving as a neuroendocrine link between the brain and the PITUITARY GLAND.	Eminentia Mediana,Medial Eminence,Eminence, Medial,Eminence, Median,Eminences, Medial,Eminentia Medianas,Medial Eminences,Mediana, Eminentia,Medianas, Eminentia
D010904	Pituitary Gland, Posterior	Neural tissue of the pituitary gland, also known as the neurohypophysis. It consists of the distal AXONS of neurons that produce VASOPRESSIN and OXYTOCIN in the SUPRAOPTIC NUCLEUS and the PARAVENTRICULAR NUCLEUS. These axons travel down through the MEDIAN EMINENCE, the hypothalamic infundibulum of the PITUITARY STALK, to the posterior lobe of the pituitary gland.	Neurohypophysis,Infundibular Process,Lobus Nervosus,Neural Lobe,Pars Nervosa of Pituitary,Posterior Lobe of Pituitary,Gland, Posterior Pituitary,Infundibular Processes,Lobe, Neural,Lobes, Neural,Nervosus, Lobus,Neural Lobes,Pituitary Pars Nervosa,Pituitary Posterior Lobe,Posterior Pituitary Gland,Posterior Pituitary Glands,Process, Infundibular,Processes, Infundibular
D011388	Prolactin	A lactogenic hormone secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). It is a polypeptide of approximately 23 kD. Besides its major action on lactation, in some species prolactin exerts effects on reproduction, maternal behavior, fat metabolism, immunomodulation and osmoregulation. Prolactin receptors are present in the mammary gland, hypothalamus, liver, ovary, testis, and prostate.	Lactogenic Hormone, Pituitary,Mammotropic Hormone, Pituitary,Mammotropin,PRL (Prolactin),Hormone, Pituitary Lactogenic,Hormone, Pituitary Mammotropic,Pituitary Lactogenic Hormone,Pituitary Mammotropic Hormone
D004295	Dihydroxyphenylalanine	A beta-hydroxylated derivative of phenylalanine. The D-form of dihydroxyphenylalanine has less physiologic activity than the L-form and is commonly used experimentally to determine whether the pharmacological effects of LEVODOPA are stereospecific.	Dopa,3,4-Dihydroxyphenylalanine,3-Hydroxy-DL-tyrosine,Dihydroxyphenylalanine Hydrochloride, (2:1),beta-Hydroxytyrosine,3 Hydroxy DL tyrosine,3,4 Dihydroxyphenylalanine,beta Hydroxytyrosine
D004298	Dopamine	One of the catecholamine NEUROTRANSMITTERS in the brain. It is derived from TYROSINE and is the precursor to NOREPINEPHRINE and EPINEPHRINE. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. A family of receptors (RECEPTORS, DOPAMINE) mediate its action.	Hydroxytyramine,3,4-Dihydroxyphenethylamine,4-(2-Aminoethyl)-1,2-benzenediol,Dopamine Hydrochloride,Intropin,3,4 Dihydroxyphenethylamine,Hydrochloride, Dopamine
D004302	Dorsomedial Hypothalamic Nucleus	An aggregation of cells in the middle hypothalamus dorsal to the ventromedial nucleus and bordering the THIRD VENTRICLE.	Hypothalamic Nucleus, Dorsomedial,Nucleus, Dorsomedial Hypothalamic
D004558	Electric Stimulation	Use of electric potential or currents to elicit biological responses.	Stimulation, Electric,Electrical Stimulation,Electric Stimulations,Electrical Stimulations,Stimulation, Electrical,Stimulations, Electric,Stimulations, Electrical
D005260	Female		Females
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia