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Z S Han

Publications and source records attributed to Z S Han.

11 recordsLinked to original sources
PubMed1992

Responses of neurons in the rat anterior hypothalamic periventricular zone to osmotic stimulation and angiotensin II in vitro.

Extracellular recordings were made in vitro from neurons in slices of the rat periventricular zone surrounding the anterior portion of the third ventricle. Spontaneous unit activity of these neurons was decreased in 39.5% of the neurons tested, increased in 32.9%, and biphasically changed (i.e., excitation-inhibition) in 10.5%, in response to bath application of hypertonic artificial cerebrospinal fluid (aCSF) containing elevated levels of NaCl (330 mOsm). Similar responses were observed following bath application of hypertonic aCSF prepared with additional mannitol. Angiotensin II in the perfusion medium dramatically increased spontaneous unit activity in 73.7% of neurons tested, while, unexpectedly, 5.3% were inhibited. These results suggest that some neurons in the periventricular zone are themselves osmosensitive, and may be involved in the regulation of water balance.

Angiotensin II↗
PubMed1992

Neuronal responses of the anterior commissural nucleus to osmotic stimulation and angiotensin II in hypothalamic slices in the rat.

The firing rate and pattern of activity of neurons in the anterior commissural nucleus (ACN), which was rich in oxytocin-containing neurons, were studied electrophysiologically in hypothalamic slices. Extracellular recording showed that most ACN neurons exhibited irregular or regular continuous spontaneous unit activity. Other neurons showed short burst patterns of activity or were silent. The majority of ACN neurons were activated by bath application of angiotensin II, and a substantial number of them showed inhibitory or excitatory responses to hypertonic bathing medium. These results indicate that magnocellular neurosecretory neurons in the ACN may participate in the regulation of water balance.

Angiotensin II↗
PubMed1991

Convergence of somatosensory and baroreceptive inputs onto parabrachio-subfornical organ neurons in the rat: an electrophysiological study.

Electrophysiological characteristics were described for neurons of the parabrachial nucleus (PBN) which receive baroreceptive and somatosensory inputs in the rat. Following focal electrical stimulation in the ipsilateral caudal nucleus of the tractus solitarii (NTS), the firing rates of these neurons were increased in 94 (55.6%), and decreased in 38 (22.5%). Fifty-three (54.5%) of 97 PBN neurons tested were excited, and 11 (11.3%) inhibited in response to contralateral common peroneal nerve (CPN) stimulation. Of these neurons, 52 were found to respond to both caudal NTS and CPN stimulation. Effects of subfornical organ (SFO) stimulation were also examined in 151 of 169 parabrachial neurons. 13 (7.7%) were activated antidromically and were located in the lateral division of the PBN, while 34 (22.5%) were affected orthodromically. Stimulation of the caudal NTS resulted in both a fall in the heart rate and changes of PBN neuronal firing rates. Similar effects were elicited by activating peripheral baroreceptors by the administration of phenylephrine, an alpha-adrenergic agonist. These results strongly indicate that: (1) the lateral PBN is involved in central cardiovascular control; (2) somatosensory and baroreceptive messages may converge onto some PBN neurons; and (3) some PBN neurons may relay baroreceptive information from the caudal NTS to the SFO.

Action Potentials↗
PubMed1991

[Responses of neurons in lateral parabrachial nucleus to antidromic stimulation of subfornical organ and to orthodromic stimulation of nucleus tractus solitarius in the rat].

Single unit discharges were extracellularly recorded from the neurons in the lateral parabrachial nucleus (LPBN) and responses of the recorded units to antidromic stimulation of the subfornical organ (SFO) and to orthodromic stimulation of the nucleus tractus solitarius (NTS) were observed in urethane-anesthetized rats. Following electrical stimulation of the SFO, 9.9% (51/151) of the LPBN units were antidromically activated. After activation of peripheral baroreceptors by raising arterial blood pressure with an intravenous injection of phenylephrine, 40.7% (22/54) of the LPBN units were inhibited and 27.8% (17/54) excited. Following orthodromic stimulation of the depressor area in the NTS, 55.6% (94/169) of the LPBN units showed an increase and 22.5% (38/169) a decrease in firing rates. Among the LPBN neurons antidromically activated by SFO stimulation, 2 units were inhibited by phenylephrine administrated i.v.; of the 8 units tested, when the NTS was stimulated, 6 were excited and 2 inhibited. The results suggest that the LPBN neurons may receive inhibitory or excitatory baroreceptive inputs from the NTS and then relay it directly to SFO.

Animals↗
PubMed1990

Effects of electrical stimulation of the central nucleus of the amygdala and the lateral hypothalamic area on the oval nucleus of the bed nuclei of the stria terminalis and its adjacent areas in the rat.

Our recent studies demonstrated that there are reciprocal connections between the oval nucleus (Ov) of the bed nuclei of the stria terminalis (BST) and the central nucleus of the amygdala (Ce) or the lateral hypothalamic area (LHA). The present experiments found that spontaneous unit discharges of 73 neurons in the Ov and its adjacent areas were modified in 58 neurons (79.45%) by focal brain stimulation in the Ce. After focal LHA stimulation, the spontaneous unit discharges of 23 (53.49%) of 43 Ov neurons, which could be influenced by focal Ce stimulation, were changed. Thirteen Ov neurons were antidromically activated by focal Ce or LHA stimulation. These results indicate that: (1) neuronal activities in the Ov and its adjacent areas can be modulated by Ce or LHA; (2) there are functional reciprocal connections between Ov and Ce or LHA; and (3) the Ce and LHA afferents converge upon some Ov neurons.

Action Potentials↗
PubMed1989

Fluorogold as a retrograde tracer used in combination with immunohistochemistry.

The fluorescent dye Fluorogold has been recently introduced as a retrograde neuronal tracer that can be used in combination with immunohistochemistry. It has, however, lately been reported that immunohistochemical processes induced rapid photobleaching of Fluorogold. In the present study we prove that it is the water in the sections, and not the immunohistochemical processing itself, that is responsible for the photobleaching. This problem is easily corrected by using a 29:1 or 19:1 glycerine-PBS buffer mounting medium.

Animals↗