Distribution of glutamate- and GABA-immunoreactive neurons projecting to the vasomotor center of the intermediolateral nucleus of the lower thoracic cord of Wistar rats: a double-labeling study

Recording experiments were done in chloralose-anesthetized, paralyzed, and artificially ventilated cats to identify single units in the ventrolateral medulla (VLM) projecting directly to the region of the intermediolateral nucleus of the spinal cord (T2) and responding to selective activation of peripheral chemoreceptors (sodium cyanide, 20-60 micrograms in 0.1-0.3 ml saline into medial thyroid artery) and baroreceptors (phenylephrine, 2 micrograms/kg iv). The firing frequency of 49 of the 81 antidromically identified single units was altered by activation of the peripheral cardiovascular receptors. Of these responsive units, 25 responded only to activation of chemoreceptors (17 excited and 8 inhibited), 20 responded in various combinations to activation of both chemo- and baroreceptors, and 4 responded only to activation of baroreceptors. In addition, units that altered their firing frequency during baroreceptor activation (n = 24) responded in the opposite direction to baroreceptor unloading (carotid arterial occlusion). These results suggest that neurons in the VLM are components of bulbospinal sympathoexcitatory and -inhibitory pathways that receive cardiovascular afferent information and in turn influence vasoconstrictor and cardioacceleratory neurons in the intermediolateral nucleus of the upper thoracic cord.

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Microinjection of substance P and ACh into rat intermediolateral nucleus elicits cardiovascular responses

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1990.259.2.r357 ◽

1990 ◽

Vol 259 (2) ◽

pp. R357-R361

Author(s):

F. R. Calaresu ◽

D. J. McKitrick ◽

E. J. Weernink

Keyword(s):

Spinal Cord ◽

Heart Rate ◽

Substance P ◽

Wistar Rats ◽

Artificial Ventilation ◽

Cardiovascular Responses ◽

Male Wistar Rats ◽

Excitatory Responses ◽

The Right ◽

Intermediolateral Nucleus

The effects of substance P (SP) or acetylcholine (ACh) microinjected into the intermediolateral nucleus of the spinal cord (IMLn) on arterial pressure (AP) and heart rate (HR) were investigated in 22 male Wistar rats under urethan and artificial ventilation. L-Glutamate (Glu) was microinjected into the IMLn between C7 and T4 to locate cardiovascular sites. Micropipettes containing Glu were stereotaxically positioned in 82 histologically verified sites in the IMLn between C7 and T4 on both the right and left sides. Microinjection of 4-10 nl of 0.18 M Glu in 30 of 39 explored sites at the T2 level elicited significant increases in HR (+24.2 +/- 3.1 beats/min). These changes were accompanied by significant increases in mean AP (+11.4 +/- 1.2 mmHg) at the T2 level (32/47 sites). Microinjection of 4-10 nl of SP (3 X 10(-7) to 3 X 10(-4) M) or ACh (0.005-0.5 M) in the right IMLn at the T2 level elicited increases in HR but did not affect AP. The duration of the responses to SP or ACh was significantly longer than the duration of the responses to Glu. The responses to ACh could be blocked by prior microinjection of 5 X 10(-2) M atropine. No responses were ever obtained in the left IMLn by microinjection of Glu, SP, or ACh. These results support the hypothesis that Glu, ACh, and SP mediate sympathoexcitation in the IMLn of the rat and that these excitatory responses have different temporal patterns.

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Ultrastructural Investigation of Spontaneous Pituitary Adenomas in Aging Sprague-Dawley Rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053747 ◽

1982 ◽

Vol 40 ◽

pp. 216-217

Author(s):

D. J. McComb ◽

J. Beri ◽

F. Zak ◽

K. Kovacs

Keyword(s):

Microscopic Study ◽

Pituitary Adenomas ◽

Wistar Rats ◽

Microscopic Level ◽

Sprague Dawley ◽

Prolactin Cells ◽

Light Microscopic Level ◽

Ultrastructural Investigation ◽

Sprague Dawley Rats ◽

Long Evans

Investigation of the spontaneous pituitary adenomas in rat have been limited mainly to light microscopic study. Furth et al. (1973) described them as chromophobic, secreting prolactin. Kovacs et al. (1977) in an ul trastructural investigation of adenomas of old female Long-Evans rats, found that they were composed of prolactin cells. Berkvens et al. (1980) using immunocytochemistry at the light microscopic level, demonstrated that some spontaneous tumors of old Wistar rats could contain GH, TSH or ACTH as well as PRL.

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Light and electron microscopic investigation of adenohypophyses of germfree, food-restricted, and germfree-food restricted aging, male lobund-wistar rats

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103826 ◽

1988 ◽

Vol 46 ◽

pp. 352-353

Author(s):

G. Ilse ◽

K. Kovacs ◽

N. Ryan ◽

T. Sano ◽

L. Stefaneanu ◽

...

Keyword(s):

Wistar Rats ◽

Microscopic Investigation ◽

Electron Microscopic Investigation ◽

Aging Male ◽

Sprague Dawley ◽

Electron Microscopic ◽

Sprague Dawley Rats ◽

Old Rats ◽

Ad Libitum ◽

Microscopic Findings

Germfree state and food restriction have been shown to increase life span and delay tumor occurrence in rats. We report here the histologic, immunocytochemical and electron microscopic findings of adenohypophyses of aging, male Lobund-Wistar rats raised at Lobund Laboratories. In our previous study, the morphologic changes in the adenohypophyses of old rats have been extensively investigated by histology, immunocytochemistry and electron microscopy. Lactotroph adenomas were frequent in Long-Evans and Sprague-Dawley rats, whereas gonadotroph adenomas were frequent in Sprague-Dawley and Wistar rats.Male Lobund-Wistar rats were divided into four groups: 1) conventional, which were raised under normal non-germfree environment and received food ad libitum; 2) germfree-food ad libitum; 3) conventional environment-food restricted and 4) germfree-food restricted. The adenohypophyses were removed from 6-month-, 18-month- and 30-month-old rats. For light microscopy, adenohypophyses were fixed in formalin and embedded in paraffin.

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Surface epithelial ultrastructure of the polycystic ovary in the BB wistar rat

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100142888 ◽

1986 ◽

Vol 44 ◽

pp. 252-253

Author(s):

R. C. Kaufmann ◽

F. K. Khosho ◽

K. S. Amankwah

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Wistar Rats ◽

Polycystic Ovary ◽

Wistar Rat ◽

Polycystic Ovaries ◽

Chemical Diabetes ◽

Scanning Electron

Diabetes decreases the fertility of females, but the mechanisms are not completely understood. In our investigations, we have found that 13% of the female BB Wistar rats that spontaneously developed chemical diabetes had persistent estrous. In this study the ovaries of these rats were examined by scanning electron microscopy(SEM) and compared to normal-cycling controls as well as to rats that had developed polycystic ovaries(PCO) by exposure to constant 1ight.

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Structural and functional renal alterations in five-sixth nephrectomized rats on unrestricted diet

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010014333x ◽

1986 ◽

Vol 44 ◽

pp. 342-343

Author(s):

I. Stachura ◽

M. Pardo ◽

J. Costello ◽

D.M. Landwehr

Keyword(s):

Wistar Rats ◽

Renal Damage ◽

Standard Diet ◽

Experimental Conditions ◽

Phosphate Intake ◽

Dietary Restrictions ◽

Severe Reduction ◽

Male Wistar Rats ◽

Unrestricted Diet ◽

Progressive Renal Insufficiency

Under experimental conditions severe reduction of renal mass results in the hyperfiltration of the remaining nephrons leading to a progressive renal insufficiency. Similar changes are observed in patients with various renal disorders associated with a loss of the functioning nephrons. The progression of renal damage is accelerated by high protein and phosphate intake, and may be modified by the dietary restrictions.We studied 50 five-sixth nephrectarrized male Wistar rats on a standard diet (Rodent Laboratory Chow 5001 Ralston Purina Co., Richmond, Indiana; containing 23.4% protein) over a 20 week period.

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