Central cholinergic pathways in the rat: an overview based on an alternative nomenclature (Ch1-Ch6).

Preface .............................................................. 649

The functional states of the thalamus and the associated neuronal interplay.

2. Evidence for A m i n o Acids as T ransmi t t e r s . . . . . . . . . . . . . . . . . . . . 99 2.1. Synthesis and Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . 100 2.2. Synapt ic Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 2.3. Postsynapt ic Act ion . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 2.4. Postsynapt ic An tagon i s t s . . . . . . . . . . . . . . . . . . . . . . . . . 103 2.5. Inac t iva t ion and R e m o v a l . . . . . . . . . . . . . . . . . . . . . . . . . 104

Amino acid transmitters in the mammalian central nervous system

The role of monoamines and acetylcholine-containing neurons in the regulation of the sleep-waking cycle

Histamine is a transmitter in the nervous system and a signaling molecule in the gut, the skin, and the immune system. Histaminergic neurons in mammalian brain are located exclusively in the tuberomamillary nucleus of the posterior hypothalamus and send their axons all over the central nervous system. Active solely during waking, they maintain wakefulness and attention. Three of the four known histamine receptors and binding to glutamate NMDA receptors serve multiple functions in the brain, particularly control of excitability and plasticity. H1 and H2 receptor-mediated actions are mostly excitatory; H3 receptors act as inhibitory auto- and heteroreceptors. Mutual interactions with other transmitter systems form a network that links basic homeostatic and higher brain functions, including sleep-wake regulation, circadian and feeding rhythms, immunity, learning, and memory in health and disease.

Histamine in the Nervous System

Depression of spinal motoneurones by noradrenaline, 5-hydroxytryptamine and histamine

1. L-Noradrenaline (NA), dopamine, 5-hydroxytryptamine (5-HT) and lysergide were administered iontophoretically to neurones in the dorsal lateral geniculate nucleus of the cat and the responses to these drugs recorded.

2. Many neurones were depressed by the monoamines and lysergide.

3. This depression was manifested by a reduction or abolition of the effects of optic nerve or visual stimulation, by a failure in some instances of an antidromically propagating spike to invade the cell soma, and by a depression of the excitant effects of L-glutamate and acetylcholine.

4. Although there was considerable variation in the magnitude of the depressant effects of the monoamines, dopamine was found to be slightly more potent than 5-HT and NA. Neurones which were inhibited by catecholamines did not always respond to 5-HT and lysergide and vice versa.

5. The inhibitory actions of monoamines on lateral geniculate neurones are comparable with those that have been recorded in other structures of the central nervous system.

6. Lysergide did not antagonize the action of 5-HT.

7. Catecholamines and 5-HT are present in nerve terminals in the lateral geniculate nucleus and the findings of this study suggest that they act as inhibitory transmitters.

https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/jphysiol.1967.sp008228

The inhibitory action of monoamines on lateral geniculate neurones

https://bpspubs.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1476-5381.1968.tb00492.x

Histamine and some antihistamines: their actions on cerebral cortical neurones.

1. The dorsal lateral geniculate nucleus (LGN) of the cat stains densely for acetylcholinesterase, which is present in intra-axonal and extracellular locations.



2. Acetylcholine (ACh), cholinomimetic drugs, anticholinesterases and ACh antagonists were administered iontophoretically to neurones in the LGN.



3. ACh excited eighty-six of 184 (46·7%) geniculate neurones and depressed seven (3·8%).



4. The excitatory response to ACh was frequently larger than that to L-glutamate and had a comparable time course.



5. There was a considerable variation in the proportion of ACh sensitive cells in different animals. ACh firing was facilitated by optic nerve or visual stimulation.



6. Carbamylcholine was the most active of the choline esters tested, frequently exceeding ACh in potency. The other choline esters and nicotine were consistently less active than ACh.



7. Anticholinesterases, eserine, neostigmine and edrophonium potentiated the action of ACh, and often caused excitation. Eserine caused an initial small enhancement in the amplitude of the focal potential evoked by optic nerve stimulation followed by a reduction in amplitude and prolongation of duration of the potential.



8. Atropine and benzoquinonium effectively prevented the ACh excitation of many cells. Dihydro-β-erythroidine failed to cause a significant reduction in the magnitude of the ACh response. All three ACh antagonists failed to reduce the excitant effects of optic nerve or visual stimulation.



9. Stimulation of the mesencephalic reticular formation caused either an enhancement or a reduction in the excitability of ACh sensitive neurones in the LGN. Benzoquinonium abolished the excitatory effects of reticular formation stimulation.



10. The findings presented in this paper suggest that ACh is the transmitter released by terminals of nerves of the reticular formation projection to the LGN.

https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/jphysiol.1967.sp008326

A study of cholinoceptive cells in the lateral geniculate nucleus.

/pdf/pharmacological-studies-on-the-heart-of-tapes-watlingi-a-bgbuoxr7si.pdf

J. W. Phillis

Papers

Depression of spinal motoneurones by noradrenaline, 5-hydroxytryptamine and histamine

The inhibitory action of monoamines on lateral geniculate neurones

Histamine and some antihistamines: their actions on cerebral cortical neurones.

A study of cholinoceptive cells in the lateral geniculate nucleus.

Pharmacological studies on the heart of Tapes watlingi: a mollusc of the family Veneridae.