We have studied the density of the microvascular system of the pia matter and perfusion and oxygen saturation of the sensorimotor cortex in hypertonic rats of different ages. We have found that the density of the microvascular system did not decrease, but increased, with age. The perfusion of the cortex decreased, and oxygen saturation of brain tissues increased. By the age of 12 months, the exploratory behavior of rats in an open-field test worsened significantly by all parameters.

Male Wistar-Kyoto rats received intracerebral transplantation of syngeneic mesenchymal stem cells (MSCs) at 22–24 months of age. The cognitive function of these animals was tested and the microvasculature density, tissue blood-flow rate, and oxygen saturation of mixed blood in the cortical microvasculature were measured in the sensorimotor cortex of the contralateral brain hemisphere under standard conditions, after norepinephrine application, and in global ischemia 3 weeks after cell transplantation. Rats at 2–3 and 22–24 months of age were used as the control groups. MSC transplantation had a positive impact on microcirculation in the cerebral cortex of old animals: deterioration of the vascular bed was prevented and the level of oxygen saturation of blood in the microvasculature was elevated; therefore, the tolerance of animals to the spasm of pial arterioles and global cerebral ischemia was increased, although aging-related decline of cognitive functions was not alleviated.

Male Wistar-Kyoto rats, aged 22-24 months, were intracerebrally transplanted syngeneic mesenchymal stem cells (MSC). Cognitive functions of these animals were tested in 3 weeks. The density of microvascular bed, the tissue blood flow, saturation of mixed blood in cortex microvessels were measured under the standard conditions, under the impact of noradrenaline and in the context of global ischemia. The control groups consisted of rats aged 2-3 months and 22-24 months. MSC transplantation have a positive impact on the microcirculation in brain cortex of old animals: reduction of vascular density was prevented, level of saturation in the blood vessels was increased, which enabled animals to endure easier extreme impacts, but did not correct age-related deterioration of cognitive functions.

We transplanted syngenetic bone marrow mesenchymal stem cells (BM MSCs) obtained from 3- to 4-month-old or 20- to 22-month-old donors into the brain of 22- to 24-month-old male Wistar–Kyoto rats. Using a TV device to study microcirculation in vivo, we found that transplantation of BM MSCs from young donors increased the densities of the microvascular network in the pia mater of the sensorimotor cortex and of the arteriolar compartment in old rats approximately by values of 1.9 and 2.1 as compared to agematched controls. Transplantation of BM MSCs from old donors did not significantly influence the density of the microvascular network in the pia mater, while the density of the arteriolar compartment increased by approximately 1.5 times.

Cerebral blood vessel reactivity is one of the main determinants of final outcome of brain ischemia. Most of studies on the vascular mechanisms of ischemic brain injury, however, focus on the acute changes within ischemic period or several hours after it. Dilatatory capacity of cerebral arterioles (perfusion reservoir) is considered as an important factor of brain perfusion elevation in critical situations.The aim of the present study was to examine the pial vessel reactivity in response to hypercapnia in rats, subjected to transient global cerebral ischemia, at 7, 14 and 21 days after ischemia. Materials and methods. Transient global cerebral ischemia was induced in anesthetized Wistar rats by bilateral common carotid artery occlusion for 12 min with simultaneous controlled hypotension to 45±3 mm Hg, followed by blood reinfusion and recovery from anesthesia. Three different groups of rats were re-anesthetized at 7, 14 or 21 days after ischemia and subjected to microvascular reactivity studies using in vivo video microscopy. Hypercapnia was caused by i.v. injection of acetazolamide. The changes in diameter of pial arteries and veins in response to hypercapnia were measured. Results and discussion. Global cerebral ischemia led to marked decrease in pial vessels (both arteries and veins) reactivity in response to hypercapnia, caused by i.v. injection of acetazolamide. In intact rats, i.v. injection of acetazolamide led to pial arteries dilation and pial veins constriction; in animals subjected to ischemia-reperfuion. the numbers of dilated large arteries and constricted small veins were much less, as well as the extent of arterial dilation. Reactivity changes were observed in all time points studied. Conclusions. Thus, transient global cerebral ischemia cause marked and long lasting (3 weeks) decrease in pial vessel reactivity in response to hypercapnia.

Using a television-based vital microscopy method and immunohystochemical analysis, we have assessed the effect of intracerebral transplantation of syngeneic mesenchymal stem cells (MSC) on the brain cortex structure and the microcirculation in the pia mater of old rats. Using "open field" system, we have studied the effect of MSC transplantation on position-finding and discovery behavior of older animals. We have found that density of microvascular network of the pia mater increased ca. 1.9-fold in MSC recipients, compared to age-matched intact animals. Density of the arteriolar area of microvascular network of the pia mater increased ca. 2-fold. Reactivity of the newly formed arterioles was nearly equal to that of native microvessels. Intracerebral transplantation procedure itself was traumatic for brain cortex of rats, but it had no effect on the microcirculation in the contralateral hemisphere. Intracerebral transplantation of MSC did not improve locomotor behavi- or and emotional stage of old rats, did not increase their position-finding and discovery activity.

Male Wistar-Kyoto rats (12 and 22–24 months old) were intracerebrally transplanted with syngeneic mesenchymal stem cells (MSCs). Then, the orientation and exploratory behavior of these animals at the age of 2 years (i.e., 1 year or 3 weeks after MSC transplantation) was assessed in an “open field” test. The basic behavioral acts of the older rats (22–24 months old) were inhibited compared to the younger animals (2–3 months old). The transplantation of MSCs did not improve the orientation and exploratory behavior of old rats. The results of morphological and immunohistochemical analysis suggest that the intracerebral MSC transplantation led to partial injury of the ipsilateral hemisphere cortex.

We studied the effect of intracerebral transplantation of bone marrow mesenchymal stem cells on microcirculation (density of microvascular network and reactivity of arterioles) in the pia mater of 2-3-month-old rats. It was found that after transplantation of mesenchymal stem cells, the density of pial microcirculatory network in the contralateral hemisphere significantly increased (by 1.7 times; p <0.05) in comparison with both intact animals and controls. The number of arterioles in the studied area increased most markedly (by ~2.5 times; p <0.05) in comparison with other groups. Intracerebral transplantation of mesenchymal stem cells or conditioned culture medium (α-MEM) had no effect on reactivity of pial arterioles.

The responses of rat pial vessels to red laser irradiation can be mediated by NO. NO mainly affects major arteries and did not contribute to reactivity of small pial arteries and precortical arterioles.

Using a TV device for studying microcirculation (×40), we studied the density of the whole microvascular network and arteriolar its compartment in the pia mater of the sensorimotor cortex in rats of different age (2–3, 12, and 24 months) after intracerebral transplantation of mesenchymal stem cells or nutrient medium (control). The density of the microvascular network in the pia mater remained practically unchanged until 1 year, but then decreased by 1.8 times with adding (up to 2 years). MSC transplantation 1.5-1.8-fold increased the density of the pial microvessels in animals of all age groups in comparison with intact and control rats; the density of the arteriolar compartment increased by 2.1-2.4 times. Intracerebral injection of MSC to 1-year-old animals prevented pathological decrease in the density of microvascular network during the next year of life.

Segment-specific characteristics of the reactions of pial arteries of different generations to intravenous injection of norepinephrine were studied under conditions of instrumental stabilization of systemic blood pressure in rats with blocked α- and β-adrenoceptors.

Experiments on WKY and SHR rats showed that low-intensity laser irradiation reduced the tone of pial arterial vessels thereby potentiating the subsequent constrictor effect of norepinephrine. Irradiation in the red region of the spectrum produced a more pronounced effect in the blue region. The observed effects were less pronounced in SHR rats compared to normotensive WKY rats.

Differential characteristic of the reaction of pial arteries of various generations to intravenous administration of norepinephrine was obtained in experiments on rats under artificially stabilized systemic blood pressure.

The chuditch is a large carnivorous dasyurid marsupial. Historically it had one of the widest geographical distributions of all marsupials, encompassing much of arid Australia, but it is now restricted to the mesic south-west of Western Australia. It is therefore of interest to determine if its physiology better reflects adaptation to its historically arid or present mesic habitat. The basic physiological parameters of the chuditch conform to other marsupials. Body mass of males (1385 g) was > 400% of that predicted by phylogeny and this may be related to its carnivorous diet. Body temperature was 33.9 °C at ambient temperatures ≤ thermoneutrality, with hyperthermia occurring above thermoneutrality. Basal metabolic rate was 0.361 mL O2 g− 1 h− 1 at an ambient temperature of 31 °C. Metabolic rate increased below the thermoneutral zone by 0.038 mL O2 g− 1 h− 1 °C− 1, and above the thermoneutral zone to 0.444 ± 0.059 mL O2 g− 1 h− 1 at 33.3 °C. Standard evaporative water loss was 0.498 ± 0.071 mg g− 1 h− 1 at an ambient temperature of 26.0 °C, and increased at higher ambient temperatures due to panting and licking. Changes in wet thermal conductance largely reflected changes in evaporative heat loss, and dry thermal conductance increased at high ambient temperature due in part to posture change. Ventilatory parameters were consistent with metabolic demands in and below thermoneutrality, and suggested augmented evaporative heat loss above the thermoneutral zone. Chuditch had a high point of relative water economy of 22.6 °C, indicating favourable water economy at even moderate ambient temperatures, due to its low evaporative water loss rather than high metabolic water production. Chuditch were physiologically more similar to marsupials from arid rather than mesic habitats, better reflecting their historical distribution than their current geographical range.

1.1. Exposures for 30 min to Ca-free salines irreversibly inhibited responses of the odontophore protractor (OP) muscles of Busycon canaliculatum to ACh and high K+ salines. Under continuous field stimulation, Ca-free salines extinguished the responses within 3 min and recovery on Ca readmission was only partial.2.2. Nifedipine converted normally smooth ACh-induced depolarizations into oscillatory events generating small twitch-like contractions.3.3. Nifedipine converted normally tonic high K+ responses into depolarizations with fast spike-like action potentials generating fast twitches. The low K+induced action potentials and fast twitches of this muscle were greatly enhanced by nifedipine. Nifedipine induced rapid transient inward current pulses accompanying this twitch activity.4.4. Co2+, Cd2+ and Gd3+ all inhibited the ACh and K+ responses of the OP muscle but Gd3+ was the most consistent and potent inhibitor of these responses.5.5. Gd3+ did not affect K+- or ACh-induced depolarization levels but eliminated spike-like action potentials and the twitches they generated.6.6. When the muscle membranes were depolarized with increasing K+ subsequent ACh responses were inhibited and eventually eliminated at about −41 mV, indicating that the ACh receptor here showed voltage inactivation.7.7. Although dependent upon an influx of[Ca]0 for CIRC to effect EC coupling, this Ca appears to enter the cells by a mechanism unlike that of mammalian smooth muscle. The cellular Ca pool appears to be independently but not synergistically accessed by ACh and K+ in the induction of contractile responses.