scholarly journals Innervation of Capillaries by Local Neurons in the Cat Hypothalamus: A Light Microscopic Study with Horseradish Peroxidase

1983 ◽  
Vol 3 (4) ◽  
pp. 535-542 ◽  
Author(s):  
Marshall L. Rennels ◽  
Thomas F. Gregory ◽  
Katsukuni Fujimoto
Keyword(s):  
Cerebrospinal Fluid ◽  
Horseradish Peroxidase ◽  
Microscopic Study ◽  
Locus Ceruleus ◽  
Perivascular Spaces ◽  
Adrenergic Neurons ◽  
Light Microscopic Study ◽  
Adult Cats ◽  
Neural Influences ◽  
To Receive

The protein tracer horseradish peroxidase (HRP) has been used in an attempt to define the cell bodies of origin of “nonadrenergic” varicose axons which terminate on the walls of hypothalamic capillaries. Capillaries in this region are also known to receive direct axonal contacts from adrenergic neurons in the pontine locus ceruleus. Solutions of HRP were infused into the lateral ventricles of adult cats of either sex and permitted to circulate in the cerebrospinal fluid spaces for 10 min, 20 min, or 2 h. During these periods HRP entered the perivascular spaces around penetrating arterioles and spread into the surrounding extracellular spaces of the hypothalamus. Certain neurons in the periarteriolar neuropil were consistently labeled by the tracer after all three circulation periods. These cells, including all of their processes, could be visualized in detail. Most neurons, by contrast, did not accumulate HRP. The axons of some tracer-filled neurons terminated on the walls of capillaries in the immediate vicinity of the penetrating arteriole. The arrangement and distribution of these cells suggest that they may provide a substrate for local neural influences on the hypothalamic microcirculation.

Sedative effects of alfaxalone and hydromorphone with or without midazolam in cats: a pilot study

2021 ◽  
pp. 1098612X2199615
Author(s):  
Emily P Wheeler ◽  
Amanda L Abelson ◽  
Jane C Lindsey ◽  
Lois A Wetmore
Keyword(s):  
Pilot Study ◽  
Significant Positive Correlation ◽  
Time Correlation ◽  
Catheter Placement ◽  
Blinded Study ◽  
Sedative Effects ◽  
Sedation Scores ◽  
Adult Cats ◽  
To Receive

Objectives The aim of this pilot study was to compare the quality of sedation and ease of intravenous (IV) catheter placement following sedation using two intramuscular (IM) sedation protocols in cats: hydromorphone, alfaxalone and midazolam vs hydromorphone and alfaxalone. Methods This was a prospective, randomized and blinded study. Cats were randomly assigned to receive an IM injection of hydromorphone (0.1 mg/kg), alfaxalone (1.5 mg/kg) and midazolam (0.2 mg/kg; HAM group), or hydromorphone (0.1 mg/kg) and alfaxalone (1.5 mg/kg; HA group). Sedation scoring (0–9, where 9 indicated maximum sedation) was performed at 0, 5, 10, 15 and 20 mins from the time of injection. At 20 mins, an IV catheter placement score (0–10, where 10 indicated least resistance) was performed. Results Twenty-one client-owned adult cats were included in this study. Sedation and IV catheter placement scores were compared between groups using Wilcoxon rank sum tests. Peak sedation was significantly higher ( P = 0.002) in the HAM group (median 9; range 7–9) than in the HA group (median 7; range 3–9), and IV catheter placement scores were significantly higher ( P = 0.001) in the HAM group (median 9.5; range 7–10) compared with the HA group (median 7; range 4–9). Spearman correlations were calculated between IV catheter placement score and sedation scores. There was a significant positive correlation of average sedation over time (correlation 0.83; P <0.001) and sedation at 20 mins (correlation 0.76; P <0.001) with a higher, more favorable IV catheter placement score. Conclusions and relevance These preliminary results suggest that the addition of midazolam to IM alfaxalone and hydromorphone produced more profound sedation and greater ease of IV catheter placement than IM alfaxalone and hydromorphone alone.

Drainage of cerebral interstitial fluid into deep cervical lymph of the rabbit

1981 ◽  
Vol 240 (4) ◽  
pp. F329-F336 ◽  
Author(s):  
M. W. Bradbury ◽  
H. F. Cserr ◽  
R. J. Westrop
Keyword(s):  
Cerebrospinal Fluid ◽  
Caudate Nucleus ◽  
Subarachnoid Space ◽  
Interstitial Fluid ◽  
Bulk Flow ◽  
Perivascular Spaces ◽  
Csf Analysis ◽  
Intraventricular Injections ◽  
Intracerebral Microinjection ◽  
Do So

Lymph from the jugular lymph trunks of anesthetized rabbits has been continuously collected and radioiodinated albumin (RISA) therein estimated after microinjection of 1 microliter of 131I-albumin into the caudate nucleus, after single intraventricular injections, and during intraventricular infusions. Comparison of lymph at 7 and 25 h after intracerebral microinjection with efflux of radioactivity from whole brain suggests that about 50% of cleared radioactivity goes through lymph. Concentrations, normalized to cerebrospinal fluid (CSF), were much higher in lymph and retropharyngeal nodes after brain injection than after CSF injection or infusion. Also after brain injection, lymph and nodes contained more activity on injected side in contrast to lack of laterality after CSF administration. Calculation suggests that less than 30% of RISA cleared from brain can do so via a pool of well-mixed CSF. Analysis of tissues is compatible with much RISA draining by bulk flow via cerebral perivascular spaces plus passage from subarachnoid space of olfactory lobes into submucous spaces of nose and thus to lymph.

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