CHOLINERGIC INFLUENCES ON HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL ACTIVITY OF STRESSED RATS: AN APPROACH UTILIZING AGONISTS AND ANTAGONISTS

1978 ◽  
Vol 89 (4) ◽  
pp. 726-736 ◽  
Author(s):  
N. Sithichoke ◽  
S. F. Marotta
Keyword(s):  
Stressed State ◽  
Cholinergic System ◽  
Plasma Corticosterone ◽  
Cholinergic Receptors ◽  
Male Rats ◽  
Central Effects ◽  
Adrenocortical Activity ◽  
Hpa Response ◽  
Stimulation Of ◽  
Auditory Stress

ABSTRACT Cholinergic involvement in the regulation of the hypothalamic-pituitary-adrenocortical (HPA) system of male rats was evaluated using muscarinic (atropine and methacholine) and nicotine (mecamylamine and nicotine) agents, which were selected for their specificity on cholinergic receptors (ChR). They were administered either intracerebroventricularly (icv) to produce central effects, or ip to produce both central and peripheral effects, prior to subjecting the animals to either auditory or hypercapnic stress for 1 h. Plasma corticosterone was used as an index of HPA activity. The results suggest that central muscarinic ChR are involved in inhibiting HPA activity in both non-stressed and stressed animals, whereas central nicotinic ChR are excitatory during stress but inactive in the non-stressed state. Stimulation of peripheral nicotinic ChR appeared to potentiate the HPA response to hypercapnia, and to inhibit the central excitatory nicotinic ChR when the latter were activated in non-stressed and auditory stressed rats. These data suggest that during auditory stress the HPA system is more dependent upon the cholinergic system for its activation than during non-stressed and hypercapnic states.

CHOLINERGIC INFLUENCES ON HYPOTHALAMIC-PITUITARY-ADRENOCORTICAL ACTIVITY OF STRESSED RATS: AN APPROACH UTILIZING CHOLINE DEFICIENT DIETS

1978 ◽  
Vol 89 (4) ◽  
pp. 737-743 ◽  
Author(s):  
N. Sithichoke ◽  
L. J. Malasanos ◽  
S. F. Marotta
Keyword(s):  
Drinking Water ◽  
Cholinergic System ◽  
Adrenal Glands ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Cholinergic Activity ◽  
Deficient Diet ◽  
Adrenocortical Activity ◽  
Hpa Response

ABSTRACT Male rats were placed on choline (Ch) deficient diets for 3 to 14 days, without and with Ch (normal and large doses) supplemented in the drinking water, to determine whether altering the availability of Ch would affect the cholinergic system in relation to the latter's role in modulating the hypothalamic-pituitary-adrenocortical (HPA) system of non-stressed and stressed animals. The results indicate that the basal nonstressed activity of the HPA system, as assessed by adrenal and plasma corticosterone concentrations, was not affected by placing the animals on these diets for as long as 14 days. Furthermore, the in vitro production of corticosterone by these adrenal glands, in the presence or absence of adrenocorticotrophin, was similar to those observed in animals on a regular rat diet; however, the HPA responses to auditory (100 db) stress, and to a lesser extent hypercapnic (9 % CO2) stress, were impaired on the Ch deficient diet (14 days), and these responses were partially corrected by supplementing the diet with Ch in the drinking water. Thus, the data suggest that altering the dietary intake of Ch may affect cholinergic activity, which in turn affects the HPA response to stressors.

Pituitary response to auditory stress: effect of treatment with α-methyl-p-tyrosine. Usefulness of a factorial mixed design for statistical analysis

1976 ◽  
Vol 54 (4) ◽  
pp. 596-602 ◽  
Author(s):  
R. Collu ◽  
J.-C. Jéquier
Keyword(s):  
Inhibitory Effect ◽  
Plasma Corticosterone ◽  
Repeated Measurements ◽  
Male Rats ◽  
Stress Effect ◽  
Intraventricular Administration ◽  
Mixed Design ◽  
Gh Secretion ◽  
Plasma Gh ◽  
Auditory Stress

Eight adult male rats were chronically cannulated in the jugular vein and placed individually in a sound-attenuated cubicle. Four of the animals were also implanted with a permanent cannula in the right lateral ventricle of the brain. Each animal was submitted twice to auditory stress at a 24-h interval. Before each stress, the rats were pretreated with either saline or α-methyl-p-tyrosine (α-MT), the order of administration of the drug and its vehicle being alternated in the eight rats. The injections were made either intravenously or intraventricularly. Auditory stress significantly depressed plasma growth hormone (GH) levels irrespective of the type of pretreatment. Mean plasma GH levels were significantly lower after α-MT pretreatment. α-MT pretreated animals had higher mean plasma corticosterone (B) levels which remained unchanged during stress. Plasma follicle stimulating hormone (FSH) levels were not modified by stress nor by α-MT pretreatment. The intraventricular administration of α-MT at a dose (20 mg/kg) which is ineffective by a systemic route produced the same effects on GH and B levels as the intravenous injection (250 mg/kg). These data seem to indicate that auditory stress exerts its inhibitory effect on GH secretion through a noncatecholaminergic pathway. They show, on the other hand, the existence of a central catecholaminergic tonus, stimulatory for GH and inhibitory for B.Statistical analysis was based on a factorial mixed design for repeated measurements after logarithmic transformation of the data. The purpose, advantages and limits of this procedure are presented and discussed.

Effect of Hippocampal Stimulation on the Plasma Thyrotropin (THS) and Corticosterone Responses to Acute Cold Exposure in the Rat

1972 ◽  
Vol 50 (4) ◽  
pp. 364-367 ◽  
Author(s):  
André Dupont ◽  
Edouard Bastarache ◽  
Elemer Endröczi ◽  
Claude Fortier
Keyword(s):  
Plasma Corticosterone ◽  
Male Rats ◽  
Bipolar Electrode ◽  
Corticosterone Concentration ◽  
Hippocampal Stimulation ◽  
Hippocampal Activity ◽  
Tsh Secretion ◽  
Corticosterone Response ◽  
A Minor ◽  
Stimulation Of

Seven days after the stereotaxic implantation of a bipolar electrode in the gyrus dentatus of the hippocampus of adult male rats, exposure to cold (20 min at −5 °C) increased both plasma TSH and corticosterone concentrations, whereas exposure in association with a minor environmental disturbance (presence of an observer) suppressed the TSH response to cold and enhanced the corticosterone response. Concurrent stimulation of the hippocampus with monophasic square waves of 1.3–1.5 V, 10 c.p.s., and 0.1 ms duration was found to restore the TSH response to cold and to inhibit the secretion of adrenocorticotropin (ACTH) (as reflected by the plasma corticosterone concentration). These findings suggest that the concurrent stimulation of ACTH release and inhibition of TSH secretion induced by nonspecific stress are possibly related to depressed hippocampal activity.

DER EINFLUSS VON RESERPIN AUF DIE ANTITHYREOIDALE WIRKUNG VON KALIUMPERCHLORAT

1962 ◽  
Vol 39 (3) ◽  
pp. 423-430
Author(s):  
H. L. Krüskemper ◽  
F. J. Kessler ◽  
E. Steinkrüger
Keyword(s):  
Thyroid Gland ◽  
Male Rats ◽  
Normal Male ◽  
Tissue Respiration ◽  
List Type ◽  
Morphological Alterations ◽  
Hormone Synthesis ◽  
Stimulation Of

ABSTRACT 1. Reserpine does not inhibit the tissue respiration of liver in normal male rats (in vitro). 2. The decrease of tissue respiration of the liver with simultaneous morphological stimulation of the thyroid gland after long administration of reserpine is due to a minute inhibition of the hormone synthesis in the thyroid gland. 3. The morphological alterations of the thyroid in experimental hypothyroidism due to perchlorate can not be prevented with reserpine.

OVULATORY DISCHARGE OF GONADOTROPHINS INDUCED BY HYPOTHALAMIC STIMULATION IN CASTRATED MALE RATS BEARING A TRANSPLANTED OVARY

1966 ◽  
Vol 51 (2) ◽  
pp. 281-289 ◽  
Author(s):  
J. Moll ◽  
G. H. Zeilmaker
Keyword(s):  
Electrical Stimulation ◽  
Preoptic Area ◽  
Hypothalamic Stimulation ◽  
Male Rats ◽  
Corpora Lutea ◽  
Histological Changes ◽  
Experimental Animals ◽  
Cumulus Oophorus ◽  
Dc Current ◽  
Stimulation Of

ABSTRACT Castrated young adult inbred male rats bearing ovarian transplants were subjected to electrical stimulation of the hypothalamus. This was done in order to investigate whether discharge of ovulatory amounts of gonadotrophins could be induced in such male animals by this procedure. Bilateral stimulations with unipolar electrodes and a DC current of 1.5 mA applied during 10 seconds induced in the ovarian grafts histological changes indicating the discharge of ovulatory amounts of gonadotrophins. In animals killed one day after stimulation these changes consisted of displacement of the ova towards the centre of the follicles with loosening of the cumulus oophorus. In one animal the ova had left the follicles. In animals killed three days after stimulation numerous young corpora lutea could be observed. These results were obtained with electrode tips either close to the median eminence, or in the preoptic area. Shamstimulations were ineffective. Some of the experimental animals received progesterone pretreatment. This rendered the stimulations ineffective, if continued until the day preceding stimulation, but seemed without effect on the results of stimulation, if two or three days without progesterone preceded the stimulations.

Plasma corticosterone levels during sexual behavior in male rats

1974 ◽  
Vol 5 (2) ◽  
pp. 191-200 ◽  
Author(s):  
Henry Szechtman ◽  
Peter J Lambrou ◽  
Anthony R Caggiula ◽  
Edward S Redgate
Keyword(s):  
Sexual Behavior ◽  
Plasma Corticosterone ◽  
Male Rats

Acclimation of rats following stepwise or direct exposure to heat

1985 ◽  
Vol 59 (2) ◽  
pp. 408-412 ◽  
Author(s):  
A. R. Gwosdow ◽  
E. L. Besch ◽  
C. L. Chen
Keyword(s):  
Water Intake ◽  
Elevated Temperatures ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Controlled Environment ◽  
Physiological Changes ◽  
Evaporative Water ◽  
Initial Exposure ◽  
Direct Exposure ◽  
Food And Water Intake

The physiological changes in male rats during acclimation were studied following direct or stepwise exposure to heat (32.5 degrees C) in a controlled-environment room. The animals were exposed to each temperature for 10 days beginning at 24.5 degrees C and returning to 24.5 degrees C in the reverse order of initial exposure. Relative humidity of 50 +/- 2% and a 12-h light-dark photoperiod (light from 0900 to 2100 h) were maintained. Physiological changes in metabolic rate (MR), evaporative water loss (EWL), plasma corticosterone, body water turnover, and food and water intake were measured. The results indicate a significantly (P less than 0.001) elevated plasma corticosterone and MR in rats exposed directly to heat from control temperature (24.5 degrees C) but not in those animals exposed stepwise via 29.0 degrees C. All kinetic parameters of water pool changed (P less than 0.01) on direct exposure to heat, whereas rats exposed in a stepwise manner increased only pool turnover. In addition, exposure to experimental temperatures resulted in reduced (P less than 0.05) relative food intake and increased (P less than 0.05) water intake. Compared with the control condition of 24.5 degrees C, EWL was significantly (P less than 0.05) elevated when the animals were exposed either directly or in a stepwise fashion to 32.5 degrees C. These data suggest that the response to elevated temperatures is influenced by the temperature to which the rat is acclimated.

scholarly journals Prenatal stress induces intrauterine growth restriction and programmes glucose intolerance and feeding behaviour disturbances in the aged rat

2004 ◽  
Vol 181 (2) ◽  
pp. 291-296 ◽  
Author(s):  
J Lesage ◽  
F Del-Favero ◽  
M Leonhardt ◽  
H Louvart ◽  
S Maccari ◽  
...  
Keyword(s):  
Glucose Intolerance ◽  
Prenatal Stress ◽  
Feeding Behaviour ◽  
Maternal Stress ◽  
Plasma Corticosterone ◽  
Male Rats ◽  
Male Rat ◽  
Fasting Period ◽  
Insulin Metabolism ◽  
Foetal Growth

There is growing evidence that prenatal adversities could be implicated in foetal programming of adult chronic diseases. Since maternal stress is known to disturb the foetal glucocorticoid environment, we examined the consequences of prenatal stress on foetal growth, on glucose-insulin metabolism and on feeding behaviour in the aged male rat. In foetuses at term, maternal stress reduced body, adrenal and pancreas weight as well as plasma corticosterone and glucose levels. In aged male rats (24 months of age), prenatal stress induced hyperglycaemia and glucose intolerance and decreased basal leptin levels. Moreover, after a fasting period, they showed an increased food intake. These data suggest that maternal stress induces a long-lasting disturbance in feeding behaviour and dysfunctions related to type 2 diabetes mellitus. This programming could be linked to the early restricted foetal growth and to the adverse glucocorticoid environment in utero.

Responses of Medullary Dorsal Horn Neurons to Corneal Stimulation by CO2 Pulses in the Rat

1999 ◽  
Vol 82 (5) ◽  
pp. 2092-2107 ◽  
Author(s):  
Harumitsu Hirata ◽  
James W. Hu ◽  
David A. Bereiter
Keyword(s):  
Thalamic Nucleus ◽  
Receptive Fields ◽  
Male Rats ◽  
Cervical Cord ◽  
Type I ◽  
Type Ii ◽  
Upper Cervical ◽  
The Difference ◽  
Evoked Activity ◽  
Stimulation Of

Corneal-responsive neurons were recorded extracellularly in two regions of the spinal trigeminal nucleus, subnucleus interpolaris/caudalis (Vi/Vc) and subnucleus caudalis/upper cervical cord (Vc/C1) transition regions, from methohexital-anesthetized male rats. Thirty-nine Vi/Vc and 26 Vc/C1 neurons that responded to mechanical and electrical stimulation of the cornea were examined for convergent cutaneous receptive fields, responses to natural stimulation of the corneal surface by CO2 pulses (0, 30, 60, 80, and 95%), effects of morphine, and projections to the contralateral thalamus. Forty-six percent of mechanically sensitive Vi/Vc neurons and 58% of Vc/C1 neurons were excited by CO2 stimulation. The evoked activity of most cells occurred at 60% CO2 after a delay of 7–22 s. At the Vi/Vc transition three response patterns were seen. Type I cells ( n = 11) displayed an increase in activity with increasing CO2 concentration. Type II cells ( n = 7) displayed a biphasic response, an initial inhibition followed by excitation in which the magnitude of the excitatory phase was dependent on CO2 concentration. A third category of Vi/Vc cells (type III, n = 3) responded to CO2 pulses only after morphine administration (>1.0 mg/kg). At the Vc/C1 transition, all CO2-responsive cells ( n = 15) displayed an increase in firing rates with greater CO2 concentration, similar to the pattern of type I Vi/Vc cells. Comparisons of the effects of CO2 pulses on Vi/Vc type I units, Vi/Vc type II units, and Vc/C1 corneal units revealed no significant differences in threshold intensity, stimulus encoding, or latency to sustained firing. Morphine (0.5–3.5 mg/kg iv) enhanced the CO2-evoked activity of 50% of Vi/Vc neurons tested, whereas all Vc/C1 cells were inhibited in a dose-dependent, naloxone-reversible manner. Stimulation of the contralateral posterior thalamic nucleus antidromically activated 37% of Vc/C1 corneal units; however, no effective sites were found within the ventral posteromedial thalamic nucleus or nucleus submedius. None of the Vi/Vc corneal units tested were antidromically activated from sites within these thalamic regions. Corneal-responsive neurons in the Vi/Vc and Vc/C1 regions likely serve different functions in ocular nociception, a conclusion reflected more by the difference in sensitivity to analgesic drugs and efferent projection targets than by the CO2 stimulus intensity encoding functions. Collectively, the properties of Vc/C1 corneal neurons were consistent with a role in the sensory-discriminative aspects of ocular pain due to chemical irritation. The unique and heterogeneous properties of Vi/Vc corneal neurons suggested involvement in more specialized ocular functions such as reflex control of tear formation or eye blinks or recruitment of antinociceptive control pathways.

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