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Biomedical subjects

C A Dudley

Publications and source records attributed to C A Dudley.

49 records · Page 3Linked to original sources
PubMed1980

Intra- and extrahypothalamic luteinizing hormone-releasing hormone (LHRH) distribution in the rat with special reference to mesencephalic sites which contain both LHRH and single neurons responsive to LHRH.

In addition to hypothalamic sites known to contain LHRH, several extrahypothalamic structures in both male and female rats were discovered to contain the decapeptide. In the mesencephalon, the fasciculus retroflexus, interpeduncular nucleus and midbrain central grey contained readily detectable quantities of LHRH. Single neurons responsive to microiontophoretically applied LHRH were also discovered in the mesencephalon suggesting a physiological role for the decapeptide in neuronal events at the level of the midbrain.

Animals↗
PubMed1978

The effect of ovariectomy on the responsiveness of preoptic-septal neurons to microelectrophoresed estrogen.

Extracellular potentials were recorded from medical preoptic-septal (MPOA-S) neurons in 2-week and 3--4 month ovariectomized rats, and the effects of microelectrophoresed 17beta-estradiol hemisuccinate (17betaE2S), acetylcholine (Ach), cortisol hemisuccinate (CS) and glutamate (Glut) were studied. 17betaE2S failed to produce changes in the firing rate of the majority of MPOA-S neurons tested, but Ach excited 48% of these neurons. MPOA-S neurons showed very little response to either Glut or CS. Previous findings from this laboratory have demonstrated that MPOA-S neurons recorded in 4-day cyclic female rats will respond to 17betaE2S. Therefore, the present results suggest that the ovarian steroids are necessary for maintaining this electrical sensitivity. Also, the involvement of a specific membrane or cytoplasmic receptor is discussed.

Acetylcholine↗
PubMed1977

Coitus-induced release of luteinizing hormone in the proestrous rat: fantasy or fact?

The influences of mating on serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were evaluated in 4-day cyclic proestrous rats of the Wistar strain. Blood samples were collected via guillotine from mated and unmated controls at 1900-2000 h or 2100--2200 h. Serum LH levels were determined by two independent radioimmunoassays. There were no significant differences in LH measurement between assays. At 1900--2000 h, LH levels were high, but not significantly different, in both the mated and unmated control animals. By 2100-2200 h, serum LH concentration had dropped in unmated controls but was significantly elevated in mated animals. There was no significant elevation in FSH either 1900-2000 h or 2100--2200 h on the evening of proestrus. The data indicate that when LH levels are normally high, coitus cannot further potentiate LH release. However, when LH levels are declining, coitus is an effective and adequate stimulus to initiate elevations in serum LH.

Animals↗
PubMedDate not supplied

Iontophoretic mapping of corticotropin-releasing factor (CRF) sensitive neurons in the rat forebrain.

Iontophoretic application of corticotropin-releasing factor (CRF) onto the membrane of individual brain neurons produced changes in the spontaneous occurrence of their extracellular action potentials. Neurons in the cortex and hypothalamus tended to be excited by the application of this 41-residue peptide, while those in the thalamus and lateral septal area were inhibited. In general, neurons excited by CRF were also inhibited by the local application of dopamine (DA) and morphine (MOR), while those which were inhibited by CRF were excited by DA and MOR. Glutamate excited the majority of cells tested independent of the other peptide responses. The results suggest that CRF activates several CNS regions with some specificity, and may be involved in neuronal modulation of pituitary as well as extrapituitary events.

Animals↗
PubMedDate not supplied

Solitary hypothalamic neurons inherently express vasopressin and tyrosine hydroxylase.

Hypothalamic neurons were grown as single cells in three-dimensional culture. Solitary neurons lacking cell contacts were immunocytochemically examined for inherent expression of vasopressin (VP), tyrosine hydroxylase (TH), and luteinizing hormone releasing hormone (LHRH). Immunoreactive VP and TH were detected within a day. Sixty to eighty-five percent of neurons displayed homogeneously distributed reaction product for VP or TH. One percent exhibited intense punctate staining of somas and varicosities. Few neurons stained for LHRH. Results indicate that hypothalamic neurons can express appropriate neuropeptides and transmitter-specific products without contacting other neurons or nonneuronal cells. Thus, this culture system may provide a useful model to study intrinsic neuronal processes.

Animals↗