Enzyme Histochemical Studies on the Hypothalamus of Spontaneously Hypertensive Rates : With Special Reference to That of Rats Subjected to Various Endocrinc Interferences

Okamoto, Kozo; Tabei, Ryo; Nosaka, Shoichiro; Fukushsima, Masakazu; Yamori, Yukio; Matsumoto, Masao; Yamabe, Hiroyuki; Morisawa, Tadashi; Suzuki, Yasuhiro; Tamegai, Michiko

doi:10.1253/jcj.30.1483

Cited by 11 publications

(1 citation statement)

References 88 publications

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“…Okamoto and his collaborators (6-8) suggested a probable participation of neural factor in the development and maintenance of the hypertension in the SH rat from follow ing signs of the sympathetic hyperactivity: increased splanchnic nerve activity (7), increased activities of autonomic neurons in the hypothalamus, reflecting from the accentuated histochemical enzyme reactions (6), and morphological indication of hyperactivity of the ganglion cells in the superior cervical sympathetic ganglia (8). In the present experiments, three antiadrenergic agents (reserpine, ci-methyl DOPA and guanethidine) and a ganglion blocking agent (hexamethonium) produced a greater fall of blood pressure in the SH rats than in the N rats.…”

Section: Discussionmentioning

confidence: 99%

Depressor Responses of the Spontaneously Hypertensive Rats to the Anti-Hypertensive Agents

Nagaoka

Kikuchi

Aramaki

1969

Japanese Journal of Pharmacology

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A variety of experimental hypertensions in rats has been available for the evaluation of the anti-hypertensive agents as well as for the mechanism studies of essential hyperten sion. The spontaneously hypertensive (SH) rat with 100 per cent incidence of heredity has been separated from the Wistar rats (1). Though the hypertension develops in the early stage without certain etiology, the animals in the advanced stage exhibit the vascular lesions such as periarteritis nodosa, nephrosclerosis and cardiac lesions (2-5). Recently, Okamoto et al. (6,7) and Matsumoto (8) have indicated further some involvement of neural factors in development and maintenance of the hypertension.In order to elucidate pharmacologically the mode of the hypertension in the SH rats, the depressor responses to the anti-hypertensive agents were observed comparatively be tween in the SH and normotensive (N) rats. MATERIALS AND METHODSFor the establishment of a dose-response relationship of the anti-hypertensive agents, specific pathogen free SH* (F13,14) and N rats of 17 to 25 weeks of age were used as a group of 5 rats per one dose level of each drug. The daily administrations of the following drugs in the conventional SH and N rats were as follows: 19 female SH rats (F,,,,,) of 6 and 15 weeks of age for hydrochlorothiazide, 8 SH and 8 N rats of 10 and 19 weeks of age for cmethyl DOPA and 18 SH and 18 N rats (7 to 12 months of age) for hydralazine, reserpine and guanethidine. The animals were kept in a room at a temperature of 23 to 24°C and fed stock diet and tap water ad libitum.Systolic blood pressure was determined in unanesthetized animals using Nakao et al.'s tail cuff method (9). Heart rate was calculated from the amplified pulse waves being taken during the blood pressure measurement. The measurements were carried out at one hour before and at 1, 4, 7 or 8, 24 and 48 hours after drug administration. Prior to the administration, the animals in our experiments were accustomed to the measurement handling 2 or 3 times in the preceding week.* Production of specific pathogen free animals were carried out by us in the spontaneously hypertensive and normotensive rats.

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Section: Discussionmentioning

confidence: 99%

Depressor Responses of the Spontaneously Hypertensive Rats to the Anti-Hypertensive Agents

Nagaoka

Kikuchi

Aramaki

1969

Japanese Journal of Pharmacology

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Morphological Studies on Endocrine Organs in Spontaneously Hypertensive Rats

Tabei¹,

Maruyama²,

Kumada³

et al. 1972

Spontaneous Hypertension

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A study of TSH-synthesis of spontaneously hypertensive rats by electron microscopic morphometry and autoradiography

Fujiwara

1979

Cell Tissue Res.

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In order to compare the functional state of the anterior pituitary of spontaneously hypertensive rats (SHR) with that of nonmotensive Wistar Kyoto rats (WKR), the anterior pituitary was examined by morphometry and autoradiography at the level of electron microscopy. The relative number and the relative volume of thyrotrophs in the anterior pituitary were significantly greater in SHR compared with age-matched WKR at 0, 7, 30-33 days and 10 months of age, while the relative number of somatotrophs in SHR was significantly smaller at 1 and 10 months of age. Electron microscope autoradiographic analysis of uptake of 3H-lysine by thyrotrophs of both strains at the age of approximately one month showed that 3H-lysine was incorporated into protein and transported finally to secretory granules which migrated to near the cell membrane to be discharged. Silver grains were significantly more numerous over the thyrotrophs of SHR than over those of WKR at 30 min, 1 h, and 4 h after the injection of 3H-lysine. The present study has ascertained morphologically than a congenital hypersynthesis of TSH by the anterior pituitary occurs in SHR.

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Enzyme Histochemical Studies on the Hypothalamus of Spontaneously Hypertensive Rates : With Special Reference to That of Rats Subjected to Various Endocrinc Interferences

Cited by 11 publications

References 88 publications

Depressor Responses of the Spontaneously Hypertensive Rats to the Anti-Hypertensive Agents

Depressor Responses of the Spontaneously Hypertensive Rats to the Anti-Hypertensive Agents

Morphological Studies on Endocrine Organs in Spontaneously Hypertensive Rats

A study of TSH-synthesis of spontaneously hypertensive rats by electron microscopic morphometry and autoradiography

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