Repetitive stimulation of cyclic adenosine 3',5'-monophosphate formation by adrenergic agonists in incubated slices from rat cerebral cortex

1975 ◽  
Vol 24 (6) ◽  
pp. 1263-1265 ◽  
Author(s):  
P. Skolnick ◽  
J. Schultz ◽  
J. W. Daly
1993 ◽  
Vol 69 (2) ◽  
pp. 595-608 ◽  
Author(s):  
S. Nozaki ◽  
A. Iriki ◽  
Y. Nakamura

1. Single-unit activity was recorded from neurons in the bulbar parvocellular reticular formation (PCRF) dorsal and dorsolateral to the gigantocellular reticular nucleus near its caudal boundary, and the roles of these reticular neurons in induction of rhythmical activity of trigeminal motoneurons by repetitive stimulation of the cerebral cortex (the cortical masticatory area, CMA) were studied in the paralyzed guinea pig anesthetized with urethan or with ketamine and chlorpromazine. 2. One hundred nine PCRF neurons were activated antidromically by microstimulation in either the masseter (MA) or anterior digastric (AD) motoneuron pool in the ipsilateral trigeminal motor nucleus, and orthodromically by stimulation in the contralateral CMA. Repetitive CMA stimulation induced rhythmical burst activity in these PCRF neurons in association with the rhythmical field potential in the contralateral AD motoneuron pool induced by the same CMA stimulation. The burst was synchronous with the rhythmical AD field potential in 81 neurons, 44 and 37 of which responded antidromically to stimulation in the MA and AD motoneuron pools, respectively. The remaining 28 neurons antidromically responded to stimulation in the MA motoneuron pool, and their burst corresponded in time with the period between successive AD field potentials. 3. Spike-triggered averaging of the intracellular potentials of MA and AD motoneurons (MNs) by simultaneously recorded spontaneous spikes of the PCRF neurons, which showed rhythmical burst responses during the jaw-opening phase to repetitive CMA stimulation, revealed a monosynaptic inhibitory postsynaptic potential in MA.MNs in 12 of 34 tested pairs and a monosynaptic excitatory postsynaptic potential (EPSP) in AD.MNs in 14 of 26 tested pairs. An EPSP was also found in MA.MNs after a monosynaptic latency from triggering spikes in 11 of 37 tested PCRF neurons that showed burst activity during the jaw-closing phase. 4. We conclude that both excitatory and inhibitory premotor neurons projecting to MA.MNs as well as excitatory premotor neurons projecting to AD.MNs are located in the PCRF, and that these premotor neurons relay the output of the central rhythm generator for rhythmical jaw movements in the medial bulbar reticular formation to trigeminal motoneurons, and thus participate in induction of rhythmical activities of trigeminal motoneurons by repetitive CMA stimulation.


Neurosurgery ◽  
2007 ◽  
Vol 60 (1) ◽  
pp. 189-197 ◽  
Author(s):  
Masahiro Oinuma ◽  
Kyouichi Suzuki ◽  
Takashi Honda ◽  
Masato Matsumoto ◽  
Tatsuya Sasaki ◽  
...  

1985 ◽  
Vol 63 (8) ◽  
pp. 1007-1016 ◽  
Author(s):  
P. V. Sulakhe

Interactions of several divalent cations (Mn2+, Ca2+, Co2+, Sr2+, and Zn2+) with EGTA-inhibitable adenylate cyclase were investigated in washed membranes (particles) isolated from the gray matter of rat cerebral cortex. The EGTA-inhibitable (called sensitive) enzyme activity was assayed in the presence of Triton X-100 since this detergent caused a marked increase (up to 20-fold) in the enzyme activity. The effects of various divalent metals (all added as chloride salt) indicated the presence of two distinct sites called site I and site II. At low concentrations (less than micromolar) Mn2+, Co2+, and Ca2+ increased (up to 10-fold) the enzyme activity to the same extent and appeared to act via binding to site I (high affinity site). The rank order of affinity was Mn2+ ≥ Co2+ > Ca2+. Zn2+ showed the highest affinity and Sr2+ the lowest towards binding to site I; both these metals increased the enzyme activity to lesser extents than Mn2+, Co2+, or Ca2+. GTP was not required for the stimulation of this enzyme by low concentrations of Ca2+. The interaction of Mn2+ with site II (low affinity site) caused further increase in the enzyme activity, whereas Co2+, Ca2+, and Sr2+ were inhibitory at concentrations >10 μM. Isolated fraction contained loosely and tightly associated pools of calmodulin. Myelin basic protein, but not calcineurin, inhibited the EGTA-sensitive adenylate cyclase activity. The EGTA-insensitive enzyme activity was increased by norepinephrine by mechanisms that depended on GTP and was inhibited by Ca2+. The stimulation of the EGTA-insensitive enzyme modulated the Mg2+ requirement such that Mg2+ binding to the low affinity site (site II) apparently occurred with higher affinity. The likely significance of these results is discussed with regard to (i) the presence of two classes of adenylate cyclase in rat cerebral cortex gray matter and (ii) the regulation of their activities by calmodulin-requiring and GTP-requiring mechanisms.


1965 ◽  
Vol 111 (473) ◽  
pp. 339-344 ◽  
Author(s):  
D. Stenhouse ◽  
R. Antebi ◽  
E. M. A. Dear ◽  
R. N. Herrington ◽  
C. McCance

German (1961, 1963) reported that serum from schizophrenic patients, in contrast to that from normal individuals and non-schizophrenic patients, when applied topically to the rat cerebral cortex, increased the amplitude of potentials evoked in the somato-sensory area by stimulation of the contralateral forepaw. Furthermore, similar changes were found when urine extracts were tested in the same manner (German and Kemali, 1963; Kemali, 1964).


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