TABLE 2.
Summary of experimental procedures and stimulation parameters for reviewed studies concerning both invasive and non-invasive stimulation.
| Evoked Cell Potentials | ||||||||||||||||
| Authors | Species | Strain | Type of Stimulation | Bilateral or Unilateral Stimulation? | Structures Stimulated | Time of Day of Stimulation | Overall Stimulation Time Period | Stimulus Pulse Duration | Stimulation Frequency/voltage | Stimulation Current | Lighting Conditions During Stimulation | Anaesthesia Used During Stimulation | Time of Sacrifice | Lighting Conditions During Sacrifice | Substance Measured | Collection Method |
| Brooks et al., 1975 | Rat | White | Invasive electrical | Bilateral | Cervical sympathetic trunks | Not described | 48 s | 1 every 1.25 s | 30 Hz | Not described | Not described | Urethane | Not described | Not described | N/A | N/A |
| Ronnekleiv et al., 1980 | Rat | Sprague Dawley | Invasive Electrical | Not described | Medial habenular nucleus | Usually > 18:00 | Not described | 50– 200 μs | Up to 10 Hz | 0.001− 0.1 mA | Darkened room | Urethane | Following stimulation | Not described | N/A | N/A |
| Pazo, 1981 | Rat | Wistar | Invasive electrical | Habenular complex: bilaterally, sciatic nerve: unilaterally, septal area: unclear, optic tract: unclear | Sciatic nerve, habenular complex and adjacent stria medullary, septal area, optic tract | 10:00– 18:00 | Not described | 0.5 ms | Not described | Variable intensity | Relatively dark room with no direct light on the animals | Ether | Not described | Not described | N/A | N/A |
| Semm et al., 1981 | Guinea-pig | N/A | Invasive electrical | Bilateral | Lateral habenular nuclei | Daytime | 50−100 ms (train) | 0.5 ms | 100 Hz | 0.5 mA | Darkened room | Urethane, pentobarbitone. glucose, gallamine triethiodide mixture | Not described | Not described | N/A | N/A |
| Bowers and Zigmond, 1982 | Rat | Sprague Dawley | Invasive Electrical | Bilateral | Cervical sympathetic trunks | Night-time | Not described | 0.5, 1.0, 3.0, 5.0, and 20 ms | 10 Hz | ∼5 – 60 μA | Not described | Chloral Hydrate | Not described | Not described | N/A | N/A |
| Reuss et al., 1984 | Rat | Not described | Invasive Electrical | Bilateral | Lateral habenular nuclei | Daytime | Not described | 0.1– 0.5 ms | 1–10 Hz | 0.1–0.5 mA (occasionally up to 5 mA) | Darkened room | Urethane and pentobarbital | Not described | Not described | N/A | N/A |
| Reuss et al., 1985b | Rat | Sprague Dawley | Invasive electrical | Both | SCG | 09:00–18:00 | Not described | 0.2 ms | 10 Hz | 0.1–0.5 mA | “Natural lighting conditions” | Urethane | Not described | Not described | N/A | N/A |
| Reyes-Vazquez et al., 1986 | Rat | Sprague Dawley | Invasive electrical | Bilateral | Postganglionic nerve fibres of the SCG | Not described | Not described | 0.2 ms | 1 Hz | 0.1– 0.6 mA | Ordinary room illumination during light cycle | Urethane | Following stimulation | Not described | N/A | N/A |
| Stehle et al., 1987 | Hamster | Golden | Invasive electrical | SCG: unilateral, habenular nuclei: bilateral | SCG and lateral habenular nuclei | During the dark and light periods | <17 h | 0.2ms | 2–20 Hz | 0.2 mA for habenular and optic but up to 2mA for the SCG | Not described | Urethane | Not described | Not described | N/A | N/A |
| Evoked Cell Potentials | ||||||||||||||||
| Patel and Demaine, 1990 | Hamster | Golden | Invasive electrical | Both | SCG | up to 6 h after 15:30 | Not described | 0.5–1 ms | 10–20 Hz | 0.5–1 mA | Artificial lab lighting | Urethane | Not described | Not described | N/A | N/A |
| Pazo and Gonzalez, 1991 | Rat | Wistar | Invasive electrical | Unilateral | SCG and sciatic nerve | 09:00–18:00 | Not described | 0.5 ms | Not described | Up to 0.5 mA | “Relatively dark room with no direct light on the animal during daylight” | Urethane | Not described | Not described | N/A | N/A |
| Indoleamine Output and Enzymatic Activity | ||||||||||||||||
| Brownstein and Heller, 1968 | Rat | Holtzman | Invasive electrical | Unilateral | Preganglionic cervical sympathetic fibres | Not described | 4 h | 9 s on; 51 s off | 10 Hz | 3–5 mA | Not described but animals blinded | Ether | 4-h post-op | Not described but animals blinded | HIOMT | Pineal homogenization |
| Volkman and Heller, 1971 | Rat | Holtzman | Invasive electrical | Unilateral | Preganglionic cervical sympathetic trunk | Daytime/light phase | 1, 2, or 3 h | 10 ms for 9 s every min | 10 Hz | 2x that required to produce maximal exophthalmos in the eye (2 × 0.23 mA) | Not described | Ether | Immediately or 1-h post-stimulation cessation | Not described | AANAT | Pineal homogenization |
| Bowers and Zigmond, 1980 | Rat | Sprague Dawley | Invasive electrical | Bilateral | Cervical sympathetic trunks | >4 h after darkness onset | Animals were not stimulated past the time were lights would normally turn on | 0.5 ms | 5 Hz | 0.4–2.0 mA | Exposed to light for 15 min prior to anaesthetic administration for SCG exposure to reduce night-time AANAT levels by more than 95% | Chloral hydrate | Immediately post-stimulation – before the onset of the light period | Dim red light | AANAT | Pineal homogenization |
| Heydorn et al., 1981 | Rat (ex vivo) | Sprague Dawley | Invasive electrical | Bilateral | SCG | Not described | 1 min | 10 ms | 10 Hz (10 V) | Not described | Not described | Not described | Not described | Not described | cAMP | Pineal homogenization |
| Evoked Cell Potentials | ||||||||||||||||
| Bowers and Zigmond, 1982 | Rat | Sprague Dawley | Invasive electrical | Both | Cervical sympathetic trunks | Night (>4 h into night period) AND day (>4 h into light period) | 0.5, 1, 1.5, and 2 h | 0.5 ms | 10 Hz | 2x that require to produce maximal exophthalmos of the ipsilateral eye (values ranged for each nerve from 100–1000uA) | Not described | Chloral hydrate | Immediately following stimulation | Not described | AANAT | Pineal homogenization |
| Bowers et al., 1984a | Rat | Sprague Dawley | Invasive electrical | Bilateral | Cervical sympathetic trunks | >4 h into light period | 3 h | Not described | 5 Hz | 2x that required to produce maximal exophthalmos in the ipsilateral eye | >4 h into light period | Chloral hydrate | >7 h into light period | Dimred light | AANAT | Pineal homogenization |
| Reuss et al., 1985a | Rats | Sprague Dawley | Invasive electrical | Bilateral | PVN | Daytime experiments: 11:00–13:00; Night-time experiments: 00:00–06:00 | 15, 30, 60 min | 0.2 ms | 10 Hz | 0.1 mA | Normal artificial light | Urethane | Following stimulation | Normal artificial light but animals blinded for night-time experiments | AANAT, melatonin | Pineal homogenization |
| Olcese et al., 1987 | Rat | Sprague Dawley | Invasive electrical | Bilateral | PVN | >02:00 | 2 min | 0.2 ms | 10 Hz | 0.1 mA | Yes, but all animals blinded surgically | Urethane | 30 min post-stimulation | Artificial light but animals are blinded | Melatonin, NE | Pineal homogenization |
| Reuss et al., 1989 | Rat | Sprague Dawley | Invasive electrical | Bilateral | SCG | 10:00–14:00 | (1) 120 min; (2a + b) 15 min | (1) 0.5 ms; (2a) 0.5 ms; (2b) 1 ms | (1) 10 Hz; (2a) 10 Hz; (2b) 25 Hz | (1) 0.5 mA; (2a + b) 0.5 mA | Not described | Urethane | (1) 2 h after stimulation onset; (2) immediately following stimulation | Not described | AANAT | Pineal homogenization of 2/3 of each gland |
| Chan et al., 1989 | Rabbit | New Zealand | Invasive electrical | Unilateral | Left preganglionic cervical sympathetic trunk | Light phase | 24– 60 min | 60 ms every 2 s OR 7.5 s every 20 s | 300 Hz | 1–5 mA | Not described | Pentobarbital | Not described | Not described | Melatonin | Blood (plasma) sampling from the confluens sinuum |
| Lingappa and Zigmond, 2013 | Rat | Sprague Dawley | Invasive electrical | Bilateral | Cervical sympathetic trunks | 4–8 h into daytime | 3 h | 0.5 ms | 10, 5, 2.5, and 1 Hz (10 Hz was considered optimal for AANAT stimulation) | 0.2–0.8 mA | Not described | Chloral hydrate | Immediately after stimulation (stimulation carried out 4–8 h into daytime) | Not described | AANAT | Pineal homogenization |
| Non-invasive Stimulation | ||||||||||||||||
| McIntyre and Oxenkrug, 1984 | Rat | Sprague Dawley | Non-invasive electrical | Bilateral | Ears | Before 12:00 | One shock every day for 7 days | 0.75 s | 130 V | Not described | Not described | Not described | 2100h | Dim red light | 5-HT, melatonin, NAS | Pineal homogenization |
| Nowak et al., 1988 | Rat | Wistar | Non-invasive electrical | Bilateral | Ears | At the end of the light phase with the very final treatment being given at 22:00 | A single electric sock or 10 shocks per day over 10 consecutive days | 500 ms | 50 Hz | 70 mA (to induce tonic-clonic seizures) | Not described | Not described | 1 or 2 h after the final stimulation | Light or dim-red light | AANAT, HIOMT | Pineal homogenization |
| Oxenkrug et al., 1991 | Rat | Sprague Dawley | Non-invasive electrical | Bilateral | Ears | 10:00 | Not described | 0.75 s | 130 V | Not described | Not described | Not described | 90 min after stimulation | Not described | Melatonin, serotonin, 5-HIAA. NAS | Pineal homogenization |
| Chao et al., 2001 | Rat | Wistar | Percutaneous electrical nerve stimulation | N/A | Fengfu DU16 and Jinsuo DU8 | Not described | 30 or 60 min | Not described | 80 Hz | 1.7–2.5 mA | Not described | Sodium pentobarbital | After stimulation | Not described | Melatonin | Pineal homogenization |
| Spence et al., 2004 | Humans | Humans with anxiety and insomnia (but no diagnosed anxiety disorder) | Acupuncture | Not described | Not described | Not described | 2× a week for 5 weeks | 1 hr per session | N/A | N/A | N/A | N/A | N/A | N/A | Melatonin | Measurement of urinary melatonin metabolite aMT6s |
| Kayumov et al., 2003 | Humans | Humans with insomnia and anxiety | Acupuncture | Not described | Not described | Not described | 2× a week for 5 weeks | N/A | N/A | N/A | Not described | N/A | N/A | N/A | Melatonin | Measurement of urinary melatonin metabolite aMT6s |
| Li et al., 2014 | Rat | Zucker diabetic fatty and Zucker lean | Non-invasive electrical | Bilateral | Right side auricular concha region | 14:00–17:00 | 30 min for 34 consecutive days | Not described | 2 and 15 Hz alternating every sec | 2 mA | Not described | Isoflurane | Not described | Not described | Melatonin | Blood (plasma) sampling from the tail vein |
| Wang et al., 2015 | Rat | Zucker diabetic fatty | Non-invasive electrical | Bilateral | Right side auricular concha region | Afternoon | 30 min | Not described | 2 and 15 Hz switched every sec | 2 mA | Not described | Isoflurane | Not described | Not described | Melatonin | Blood (plasma) sampling from the tail vein |